This topic describes how to process image objects stored in Object Storage Service (OSS) by using object URLs, OSS SDKs, or API operations.

Use object URLs to process images

To process an image object by using its URL, you can add Image Processing (IMG) parameters or image style parameters to the end of the URL.
  • If the access control list (ACL) of the image object that you want to process is public read or public read/write, you can add IMG parameters or image style parameters to the URL of the object to process the image.
  • If the ACL of the image object that you want to process is private, you can use OSS SDKs to add IMG operations to the URL of the object to process the image.
Notice By default, when you use a URL to access an image object in a bucket, the image is downloaded. To ensure that an image object is previewed when you access the image object, you must map a custom domain name to your bucket and add a CNAME record. For more information, see Map custom domain names.

Image objects whose ACL is public read or public read/write

The following table describes the parameters that you can add to the URL of an image object.

Image processing mode Configure IMG parameters Add image style parameters
IMG URL https://bucketname.endpoint/objectname?x-oss-process=image/action,parame_value https://bucketname.endpoint/objectname?x-oss-process=style/stylename
Parameter
  • https://bucketname.endpoint/objectname: the URL of the image object. For more information about how to obtain the URL of an object, see How do I obtain the URL of an uploaded object?
  • x-oss-process=image/: a fixed parameter, which indicates that the image object is processed by adding IMG parameters.
  • action, param_value: the action, parameter, and value of an IMG operation. These parameters determine the IMG operation that is used to process the image object. Separate multiple operations with forward slashes (/). OSS processes images in the order of IMG parameters. For example, image/resize,w_200/rotate,90 indicates that OSS resizes the image to the width of 200 pixels, and then rotates the image 90 degrees. For more information about the supported IMG parameters, see IMG parameters.
  • https://bucketname.endpoint/objectname: the URL of the image object. For more information about how to obtain the URL of an object, see How do I obtain the URL of an uploaded object?
  • x-oss-process=style/: a fixed parameter, which indicates that the image object is processed by adding image style parameters.
  • stylename: the name of the style that you set in the OSS console. For more information about how to specify an image style, see Create a style.

If a custom delimiter is specified, you can use the delimiter to replace ? x-oss-process=style/. This simplifies the IMG URL. For example, if you set the delimiter to an exclamation point (!), the URL of the processed image object is <https://bucketname.endpoint/objectname!stylename. For more information about how to configure custom delimiters, see the "Configure source image protection" section in Configure image styles.

Example https://image-demo.oss-cn-hangzhou.aliyuncs.com/example.jpg?x-oss-process=image/resize,w_300/quality,q_90 https://image-demo.oss-cn-hangzhou.aliyuncs.com/example.jpg?x-oss-process=style/panda_style

Image objects whose ACL is private

The following code provides examples on how to generate a signed URL with IMG parameters by using OSS SDKs for common programming languages. For more information about how to generate a signed URL with IMG parameters by using OSS SDKs for other programming languages, see Overview.

import com.aliyun.oss.*;
import com.aliyun.oss.model.GeneratePresignedUrlRequest;
import java.net.URL;
import java.util.Date;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify the actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. The full path cannot contain the name of the bucket. 
        String objectName = "exampleobject.jpg";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            // Resize the image to a height and width of 100 pixels, and rotate the image 90 degrees. 
            String style = "image/resize,m_fixed,w_100,h_100/rotate,90";
            // Set the validity period of the signed URL to 10 minutes. 
            Date expiration = new Date(new Date().getTime() + 1000 * 60 * 10 );
            GeneratePresignedUrlRequest req = new GeneratePresignedUrlRequest(bucketName, objectName, HttpMethod.GET);
            req.setExpiration(expiration);
            req.setProcess(style);
            URL signedUrl = ossClient.generatePresignedUrl(req);
            System.out.println(signedUrl);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}
<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\OssClient;

// Security risks may arise if you use the AccessKey pair of an Alibaba Cloud account to access OSS because the account has permissions on all API operations. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
$accessKeyId = "yourAccessKeyId";
$accessKeySecret = "yourAccessKeySecret";
// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if your bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. 
$endpoint = "yourEndpoint";
// Specify the name of the bucket. Example: examplebucket. 
$bucket= "examplebucket";
// Specify the full path of the object. Example: exampledir/exampleobject.jpg. The full path of the object cannot contain the bucket name. 
$object = "exampledir/exampleobject.jpg";

$ossClient = new OssClient($accessKeyId, $accessKeySecret, $endpoint);

// Generate a signed URL that contains the IMG parameters. The validity period of the URL is 3,600 seconds. The signed URL can be directly accessed by using a browser. 
$timeout = 3600;

$options = array(
    // Resize the image to the height and width of 100 pixels. 
    OssClient::OSS_PROCESS => "image/resize,m_fixed,h_100,w_100" );

$signedUrl = $ossClient->signUrl($bucket, $object, $timeout, "GET", $options);
print("rtmp url: \n" . $signedUrl);           
# -*- coding: utf-8 -*-
import oss2

# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
# The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
access_key_id = 'yourAccessKeyId'
access_key_secret = 'yourAccessKeySecret'
# Specify the bucket name. Example: examplebucket. 
bucket_name = 'examplebucket'
# Specify the name of the bucket in which the source image is stored. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
key = 'exampledir/example.jpg'

# Specify the bucket instance. You must use the bucket instance to call all object-related methods. 
bucket = oss2.Bucket(oss2.Auth(access_key_id, access_key_secret), endpoint, bucket_name)
# If the image does not exist in the specified bucket, you must upload the image to the bucket. 
# bucket.put_object_from_file(key, 'D:\\localpath\\example.jpg')
# After you resize the image to a height and width of 100 pixels, rotate the image 90 degrees. 
style = 'image/resize,m_fixed,w_100,h_100/rotate,90'
# Generate a signed object URL that includes IMG parameters. Set the validity period to 10 minutes. Unit: seconds. 
url = bucket.sign_url('GET', key, 10 * 60, params={'x-oss-process': style})
print(url)              
using Aliyun.OSS;
using Aliyun.OSS.Common;

// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
var endpoint = "yourEndpoint";
// The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
var accessKeyId = "yourAccessKeyId";
var accessKeySecret = "yourAccessKeySecret";
// Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
var bucketName = "examplebucket";
// Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
var objectName = "exampledir/exampledir.jpg";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
try
{
    // Resize the image to the height and width of 100 pixels. 
    var process = "image/resize,m_fixed,w_100,h_100";
    var req = new GeneratePresignedUriRequest(bucketName, objectName, SignHttpMethod.Get)
    {
        Expiration = DateTime.Now.AddHours(1),
        Process = process
    };
    // Generate a signed object URL that includes IMG parameters. 
    var uri = client.GeneratePresignedUri(req);
    Console.WriteLine("Generate Presigned Uri:{0} with process:{1} succeeded ", uri, process);
}
catch (OssException ex)
{
    Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
        ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}
package main

import (
    "fmt"
    "os"
    "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
    fmt.Println("Error:", err)
    os.Exit(-1)
}

func main() {
    // Create an OSSClient instance. 
    // Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify the actual endpoint. 
    // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
    client, err := oss.New("yourEndpoint", "yourAccessKeyId", "yourAccessKeySecret")
    if err != nil {
    HandleError(err)
    }

    // Specify the name of the bucket in which the image is stored. Example: examplebucket. 
    bucketName := "examplebucket"
    bucket, err := client.Bucket(bucketName)
    if err != nil {
    HandleError(err)
    }
    // Specify the name of the image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. 
    ossImageName := "exampledir/example.jpg"
    // Generate a signed URL that includes IMG parameters. Set the validity period of the signed URL to 600 seconds. 
    signedURL, err := bucket.SignURL(ossImageName, oss.HTTPGet, 600, oss.Process("image/format,png"))
    if err != nil {
    HandleError(err)
    } else {
    fmt.Println(signedURL)
    }
}
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
      /* Initialize the OSS account information. */
    std::string AccessKeyId = "<yourAccessKeyId>";
    std::string AccessKeySecret = "<yourAccessKeySecret>";
    std::string Endpoint = "<yourEndpoint>";
    std::string BucketName = "<yourBucketName>";
    std::string ObjectName = "<yourObjectName>";

      /* Initialize network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);


    /* Generate a signed object URL that includes IMG parameters */
    std::string Process = "image/resize,m_fixed,w_100,h_100";
    GeneratePresignedUrlRequest request(BucketName, ObjectName, Http::Get);
    request.setProcess(Process);
    auto outcome = client.GeneratePresignedUrl(request);

    /* Release network resources. */
    ShutdownSdk();
    return 0;
}
#include "oss_api.h"
#include "aos_http_io.h"
const char *endpoint = "<yourEndpoint>";
const char *access_key_id = "<yourAccessKeyId>";
const char *access_key_secret = "<yourAccessKeySecret>";
const char *bucket_name = "<yourBucketName>";
const char *object_name = "<yourObjectName>";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Use a char* string to initialize aos_string_t. */
    aos_str_set(&options->config->endpoint, endpoint);
    aos_str_set(&options->config->access_key_id, access_key_id);
    aos_str_set(&options->config->access_key_secret, access_key_secret);
    /* Specify whether to use CNAME. A value of 0 indicates that CNAME is not used. */
    options->config->is_cname = 0;
    /* Configure network parameters such as timeout periods. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int main(int argc, char *argv[])
{
    /* Call the aos_http_io_initialize method in main() to initialize global resources such as networks and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Create a memory pool to manage memory. aos_pool_t is equivalent to apr_pool_t. The code to create a memory pool is included in the APR library. */
    aos_pool_t *pool;
    /* Create a memory pool. The second parameter is NULL. This value indicates that the pool does not inherit any other memory pool. */
    aos_pool_create(&pool, NULL);
    /* Create and initialize options. This parameter specifies global configuration information such as endpoint, access_key_id, acces_key_secret, is_cname, and curl. */
    oss_request_options_t *oss_client_options;
    /* Allocate the memory resources in the memory pool to the options. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize oss_client_options. */
    init_options(oss_client_options);
    /* Initialize the parameters. */
    aos_string_t bucket;
    aos_string_t object;
    aos_table_t *params = NULL;
    aos_http_request_t *req;
    char *url_str;
    apr_time_t now;
    int64_t expire_time; 
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    /* Resize the image to a height and width of 100 pixels. */
    params = aos_table_make(pool, 1);
    apr_table_set(params, OSS_PROCESS, "image/resize,m_fixed,w_100,h_100");
    req = aos_http_request_create(pool);
    req->method = HTTP_GET;
    req->query_params = params;
    /* Specify the validity period (expire_time) in seconds. */
    now = apr_time_now();
    expire_time = now / 1000000 + 10 * 60;
    /* Generate a signed URL. */
    url_str = oss_gen_signed_url(oss_client_options, &bucket, &object, expire_time, req);
    printf("url: %s\n", url_str);
    /* Release the memory pool, which releases memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Use OSS SDKs to process images

You can configure IMG parameters or image style parameters in OSS SDKs to process images.

Configure IMG parameters

When you use IMG parameters to process images, separate multiple IMG parameters with forward slashes (/). The following code provides examples on how to configure IMG parameters by using OSS SDKs for common programming languages. For more information about how to configure IMG parameters by using OSS SDKs for other programming languages, see Overview.

import com.aliyun.oss.*;
import com.aliyun.oss.model.GetObjectRequest;
import java.io.File;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify the actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. The full path cannot contain the name of the bucket. 
        String objectName = "exampleobject.jpg";
        // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-new.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, a new file is created. 
        String pathName = "D:\\localpath\\example-new.jpg";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            // Resize the image to a height and width of 100 pixels, and rotate the image 90 degrees. 
            String style = "image/resize,m_fixed,w_100,h_100/rotate,90";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-new.jpg and save the image to your local computer. 
            // By default, if you only specify the name of a local file such as example-new.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File("D:\\localpath\\example-new.jpg"));
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}
<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\OssClient;

// Security risks may arise if you use the AccessKey pair of an Alibaba Cloud account to access OSS because the account has permissions on all API operations. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
$accessKeyId = "yourAccessKeyId";
$accessKeySecret = "yourAccessKeySecret";
// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if your bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. 
$endpoint = "yourEndpoint";
// Specify the name of the bucket. Example: examplebucket. 
$bucket= "examplebucket";
// Specify the full path of the object. Example: exampledir/exampleobject.jpg. The full path of the object cannot contain the bucket name. 
$object = "exampledir/exampleobject.jpg";
// Specify the local path to which you want to save the image. Example: D:\\localpath\\example-new.jpg. If the specified local file exists, it is overwritten by the processed image. Otherwise, the local file is created. 
// By default, if you set this parameter to the name of a local file such as example-new.jpg without specifying the local path of the file, the processed object is saved to the local path of the project to which the sample program belongs. 
$download_file = "D:\\localpath\\example-new.jpg";

$ossClient = new OssClient($accessKeyId, $accessKeySecret, $endpoint, false);
// If the image does not exist in the required bucket, you must upload the image to the required bucket. 
// $ossClient->uploadFile($bucket, $object, "D:\\localpath\\exampleobject.jpg");

// After you resize the image to the height and width of 100 pixels, rotate the image 90 degrees. 
$style = "image/resize,m_fixed,w_100,h_100/rotate,90";

$options = array(
    OssClient::OSS_FILE_DOWNLOAD => $download_file,
    OssClient::OSS_PROCESS => $style);

// Name the processed image example-new.jpg and save the image to your local computer. 
$ossClient->getObject($bucket, $object, $options);

// After the image is processed, you can delete the source image if you no longer use the image from the bucket. 
// $ossClient->deleteObject($bucket, $object);                              
# -*- coding: utf-8 -*-
import os
import oss2

# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
# The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
access_key_id = 'yourAccessKeyId'
access_key_secret = 'yourAccessKeySecret'
# Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
bucket_name = 'examplebucket'
# Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
key = 'exampledir/example.jpg'
# Specify the name of the processed image. 
new_pic = 'exampledir/newexample.jpg'

# Specify the bucket instance. You must use the bucket instance to call all object-related methods. 
bucket = oss2.Bucket(oss2.Auth(access_key_id, access_key_secret), endpoint, bucket_name)

# If the image is not stored in the specified bucket, you must upload the image from the local path to the specified bucket. 
# bucket.put_object_from_file(key, 'D:\\localpath\\example.jpg')

# After you resize the image to a height and width of 100 pixels, rotate the image 90 degrees, and save the image to your computer. 
style = 'image/resize,m_fixed,w_100,h_100/rotate,90'
bucket.get_object_to_file(key, new_pic, process=style)
# After the IMG is complete, you can delete the source image from the bucket if you no longer use the image. 
# bucket.delete_object(key)
# If you no longer use the processed image, you can delete it. 
# os.remove(new_pic)                           
using System;
using System.IO;
using Aliyun.OSS;
using Aliyun.OSS.Common;
using Aliyun.OSS.Util;
namespace ImageProcessCascade
{
    class Program
    {
        static void Main(string[] args)
        {
            Program.ImageProcessCascade();
            Console.ReadKey();
        }
        public static void ImageProcessCascade()
        {
            // Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
            var endpoint = "yourEndpoint";
            // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a Resource Access Management (RAM) user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
            var accessKeyId = "yourAccessKeyId";
            var accessKeySecret = "yourAccessKeySecret";
            // Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
            var bucketName = "examplebucket";
            // Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
            var objectName = "exampledir/example.jpg";
            // Specify the local full path of the source image. 
            // var localImageFilename = "D:\\localpath\\example.jpg";
            // Specify the local directory to which the processed image is saved. 
            var downloadDir = "yourDownloadDir";
            // Create an OSSClient instance. 
            var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
            try
            {
                // If the image does not exist in the required bucket, you must upload the image to the bucket.    
                // client.PutObject(bucketName, objectName, localImageFilename);
                // After you resize the image to the height and width of 100 pixels, rotate the image 90 degrees. 
                var process = "image/resize,m_fixed,w_100,h_100/rotate,90";
                var ossObject = client.GetObject(new GetObjectRequest(bucketName, objectName, process));
                // Specify the name of the processed image. 
                WriteToFile(downloadDir + "/yourLocalFilename", ossObject.Content);
                Console.WriteLine("Get Object:{0} with process:{1} succeeded ", objectName, process);
            }
            catch (OssException ex)
            {
                Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
                    ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed with error info: {0}", ex.Message);
            }
        }
        private static void WriteToFile(string filePath, Stream stream)
        {
            using (var requestStream = stream)
            {
                using (var fs = File.Open(filePath, FileMode.OpenOrCreate))
                {
                    IoUtils.WriteTo(stream, fs);
                }
            }
        }
    }
}
package main

import (
    "fmt"
    "os"
    "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
    fmt.Println("Error:", err)
    os.Exit(-1)
}

func main() {
    // Create an OSSClient instance. 
    // Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify the actual endpoint. 
    // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
    client, err := oss.New("yourEndpoint", "yourAccessKeyId", "yourAccessKeySecret")
    if err != nil {
    HandleError(err)
    }

    // Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
    bucketName := "examplebucket"
    bucket, err := client.Bucket(bucketName)
    if err != nil {
    HandleError(err)
     }

    // Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: exampledir/example.jpg. 
    sourceImageName := "exampledir/example.jpg"
    // Specify the name of the processed image. 
    targetImageName := "exampledir/newexample.jpg"
    // Resize the image to a height and width of 100 pixels, rotate the image 90 degrees, and save the image to your local computer. 
    style := "image/resize,m_fixed,w_100,h_100/rotate,90"
    err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(style))
    if err != nil {
     HandleError(err)
    }
}
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
     /* Initialize the OSS account information. */
    std::string AccessKeyId = "<yourAccessKeyId>";
    std::string AccessKeySecret = "<yourAccessKeySecret>";
    std::string Endpoint = "<yourEndpoint>";
    std::string BucketName = "<yourBucketName>";
    std::string ObjectName = "<yourObjectName>";

     /* Initialize network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf);

    /* After you resize the image to a height and width of 100 pixels, rotate the image 90°, and save the image to your local computer. */
    std::string Process = "image/resize,m_fixed,w_100,h_100/rotate,90";
    GetObjectRequest request(BucketName, ObjectName);
    request.setProcess(Process);
    auto outcome = client.GetObject(request);

    /* Release network resources. */
    ShutdownSdk();
    return 0;
}
#include "oss_api.h"
#include "aos_http_io.h"
const char *endpoint = "<yourEndpoint>";
const char *access_key_id = "<yourAccessKeyId>";
const char *access_key_secret = "<yourAccessKeySecret>";
const char *bucket_name = "<yourBucketName>";
const char *object_name = "<yourObjectName>";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Use a char* string to initialize aos_string_t. */
    aos_str_set(&options->config->endpoint, endpoint);
    aos_str_set(&options->config->access_key_id, access_key_id);
    aos_str_set(&options->config->access_key_secret, access_key_secret);
    /* Specify whether to use CNAME. A value of 0 indicates that CNAME is not used. */
    options->config->is_cname = 0;
    /* Configure network parameters such as timeout periods. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int main(int argc, char *argv[])
{
    /* Call the aos_http_io_initialize method in main() to initialize global resources such as networks and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Create a memory pool to manage memory. aos_pool_t is equivalent to apr_pool_t. The code to create a memory pool is included in the APR library. */
    aos_pool_t *pool;
    /* Create a memory pool. The second parameter is NULL. This value indicates that the pool does not inherit any other memory pool. */
    aos_pool_create(&pool, NULL);
    /* Create and initialize options. This parameter specifies global configuration information such as endpoint, access_key_id, acces_key_secret, is_cname, and curl. */
    oss_request_options_t *oss_client_options;
    /* Allocate the memory resources in the memory pool to the options. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize oss_client_options. */
    init_options(oss_client_options);
    /* Initialize the parameters. */
    aos_string_t bucket;
    aos_string_t object;
    aos_string_t file;
    aos_table_t *headers = NULL;
    aos_table_t *params = NULL;
    aos_table_t *resp_headers = NULL;
    aos_status_t *resp_status = NULL;
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    /* After you resize the image to a height and width of 100 pixels, rotate the image 90°. */
    params = aos_table_make(pool, 1);
    apr_table_set(params, OSS_PROCESS, "image/resize,m_fixed,w_100,h_100/rotate,90");
    /* Download the processed image to your local computer. */
    aos_str_set(&file, "<LocalFileName>");
    resp_status = oss_get_object_to_file(oss_client_options, &bucket, &object, headers, params, &file, &resp_headers);
    if (aos_status_is_ok(resp_status)) {
        printf("get object to file succeeded\n");
    } else {
        printf("get object to file failed\n");  
    }
    /* Release the memory pool, which releases memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Add image styles

You can specify an image style to encapsulate a variety of IMG parameters within the specified style, and then use the style to concurrently process multiple images. The following code provides examples on how to use image styles to process images by using OSS SDKs for common programming languages. For more information about how to use image styles to process images by using OSS SDKs for other programming languages, see Overview.

import com.aliyun.oss.*;
import com.aliyun.oss.model.GetObjectRequest;
import java.io.File;

public class Demo {
    public static void main(String[] args) throws Throwable {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify the actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. The full path cannot contain the name of the bucket. 
        String objectName = "exampleobject.jpg";
        // Specify the full path to which you want to save the processed image. Example: D:\\localpath\\example-new.jpg. If a file with the same name already exists in the path, the processed image overwrites the file. Otherwise, a new file is created. 
        String pathName = "D:\\localpath\\example-new.jpg";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            // Use the custom style to process the image. 
            // Set yourCustomStyleName to the name of the image style that you create in the OSS console. 
            String style = "style/yourCustomStyleName";
            GetObjectRequest request = new GetObjectRequest(bucketName, objectName);
            request.setProcess(style);
            // Name the processed image example-new.jpg and save the image to your local computer. 
            // By default, if you only specify the name of a local file such as example-new.jpg without specifying the local path of the file, the processed image is saved to the local path of the project to which the sample program belongs. 
            ossClient.getObject(request, new File(pathName));
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}
<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\OssClient;
// Security risks may arise if you use the AccessKey pair of an Alibaba Cloud account to access OSS because the account has permissions on all API operations. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
$accessKeyId = "yourAccessKeyId";
$accessKeySecret = "yourAccessKeySecret";
// Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if your bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. 
$endpoint = "yourEndpoint";
// Specify the name of the bucket. Example: examplebucket. 
$bucket= "examplebucket";
// Specify the full path of the object. Example: exampledir/exampleobject.jpg. The full path of the object cannot contain the bucket name. 
$object = "exampledir/exampleobject.jpg";
// Specify the local path to which you want to save the image. Example: D:\\localpath\\example-new.jpg. If the specified local file exists, it is overwritten by the processed image. Otherwise, the local file is created. 
// By default, if you set this parameter to the name of a local file such as example-new.jpg without specifying the local path of the file, the processed object is saved to the local path of the project to which the sample program belongs. 
$download_file = "D:\\localpath\\example-new.jpg";

$ossClient = new OssClient($accessKeyId, $accessKeySecret, $endpoint);

// If the image does not exist in the required bucket, you must upload the image to the required bucket. 
// $ossClient->uploadFile($bucket, $object, "D:\\localpath\\exampleobject.jpg");

// Use the custom style to process the image. 
// Set yourCustomStyleName to the name of the image style you create in the OSS console. 
$style = "style/yourCustomStyleName";

$options = array(
    OssClient::OSS_FILE_DOWNLOAD => $download_file,
    OssClient::OSS_PROCESS => $style);

// Name the processed image example-new.jpg and save the image to your local computer. 
$ossClient->getObject($bucket, $object, $options);

// After the image is processed, you can delete the source image if you no longer use the image from the bucket. 
// $ossClient->deleteObject($bucket, $object);                              
# -*- coding: utf-8 -*-
import os
import oss2
# Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
endpoint = 'https://oss-cn-hangzhou.aliyuncs.com'
# The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
access_key_id = 'yourAccessKeyId'
access_key_secret = 'yourAccessKeySecret'
# Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
bucket_name = 'examplebucket'
# Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
key = 'exampledir/example.jpg'
# Specify the name of the processed image. 
new_pic = 'exampledir/newexample.jpg'

# Specify the bucket instance. You must use the bucket instance to call all object-related methods. 
bucket = oss2.Bucket(oss2.Auth(access_key_id, access_key_secret), endpoint, bucket_name)
# If the image is not stored in the specified bucket, you must upload the image from the local path to the specified bucket. 
# bucket.put_object_from_file(key, 'D:\\localpath\\example.jpg')

# Use the custom style to process the image. Set yourCustomStyleName to the name of the image style that you create in the OSS console. 
style = 'yourCustomStyleName'
# Save the processed image to your computer. 
bucket.get_object_to_file(key, new_pic, process=style)
# After the IMG is complete, you can delete the source image from the bucket if you no longer use the image. 
# bucket.delete_object(key)
# If you no longer use the processed image, you can delete it. 
# os.remove(new_pic)
using System;
using System.IO;
using Aliyun.OSS;
using Aliyun.OSS.Common;
using Aliyun.OSS.Util;
namespace ImageProcessCustom
{
    class Program
    {
        static void Main(string[] args)
        {
            Program.ImageProcessCustomStyle();
            Console.ReadKey();
        }
        public static void ImageProcessCustomStyle()
        {
            // Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
            var endpoint = "yourEndpoint";
            // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to perform operations in OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
            var accessKeyId = "yourAccessKeyId";
            var accessKeySecret = "yourAccessKeySecret";
            // Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
            var bucketName = "examplebucket";
            // Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must add the full path of the image. Example: exampledir/example.jpg. 
            var objectName = "exampledir/example.jpg";
            // Specify the local full path of the source image. 
            // var localImageFilename = "D:\\localpath\\example.jpg";
            // Specify the local directory to which the processed image is saved. 
            var downloadDir = "yourDownloadDir";
            // Create an OSSClient instance. 
            var client = new OssClient(endpoint, accessKeyId, accessKeySecret);
            try
            {
                // If the image does not exist in the required bucket, you must upload the image to the bucket.    
                // client.PutObject(bucketName, objectName, localImageFilename);
                // Use the image style to process the image. Set yourCustomStyleName to the name of the image style you create in the OSS console. 
                var process = "style/yourCustomStyleName";
                var ossObject = client.GetObject(new GetObjectRequest(bucketName, objectName, process));
                // Specify the name of the processed image.             
                WriteToFile(downloadDir + "/yourLocalFilename", ossObject.Content);
                Console.WriteLine("Get Object:{0} with process:{1} succeeded ", objectName, process);
            }
            catch (OssException ex)
            {
                Console.WriteLine("Failed with error code: {0}; Error info: {1}. \nRequestID:{2}\tHostID:{3}",
                    ex.ErrorCode, ex.Message, ex.RequestId, ex.HostId);
            }
            catch (Exception ex)
            {
                Console.WriteLine("Failed with error info: {0}", ex.Message);
            }
        }
        private static void WriteToFile(string filePath, Stream stream)
        {
            using (var requestStream = stream)
            {
                using (var fs = File.Open(filePath, FileMode.OpenOrCreate))
                {
                    IoUtils.WriteTo(stream, fs);
                }
            }
        }
    }
}
package main

import (
    "fmt"
    "os"
    "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func HandleError(err error) {
    fmt.Println("Error:", err)
    os.Exit(-1)
}

func main() {
    // Create an OSSClient instance.    
    // Set yourEndpoint to the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set yourEndpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify the actual endpoint. 
    // The AccessKey pair of an Alibaba Cloud account has permissions on all API operations. Using these credentials to access OSS is a high-risk operation. We recommend that you use a RAM user to call API operations or perform routine O&M. To create a RAM user, log on to the RAM console. 
    client, err := oss.New("yourEndpoint", "yourAccessKeyId", "yourAccessKeySecret")
    if err != nil {
    HandleError(err)
    }

    // Specify the name of the bucket in which the source image is stored. Example: examplebucket. 
    bucketName := "examplebucket"
    bucket, err := client.Bucket(bucketName)
    if err != nil {
     HandleError(err)
    }
    // Specify the name of the source image. If the image is not stored in the root directory of the bucket, you must specify the full path of the image. Example: example/example.jpg. 
    sourceImageName := "example/example.jpg"
    // Name the processed image newexample.jpg and save the image to your local computer. 
    targetImageName := "D:\\localpath\\newexample.jpg"
    // Use the image style to process the image. In this example, set yourCustomStyleName to the name of the image style that you create in the OSS console. 
    style := "style/yourCustomStyleName"
    // Save the processed image to your local computer. 
    err = bucket.GetObjectToFile(sourceImageName, targetImageName, oss.Process(style))
    if err != nil {
    HandleError(err)
    }
}
#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
     /* Initialize the OSS account information. */
    std::string AccessKeyId = "<yourAccessKeyId>";
    std::string AccessKeySecret = "<yourAccessKeySecret>";
    std::string Endpoint = "<yourEndpoint>";
    std::string BucketName = "<yourBucketName>";
    std::string ObjectName = "<yourObjectName>";

     /* Initialize network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    OssClient client(Endpoint, AccessKeyId, AccessKeySecret, conf) ;

    /* Use the specified image style to process the image and save the image to your local computer. */
    std::string Process = "style/<yourCustomStyleName>";
    GetObjectRequest request(BucketName, ObjectName);
    request.setProcess(Process);
    auto outcome = client.GetObject(request);

    /* Release network resources. */
    ShutdownSdk();
    return 0;
}
#include "oss_api.h"
#include "aos_http_io.h"
const char *endpoint = "<yourEndpoint>";
const char *access_key_id = "<yourAccessKeyId>";
const char *access_key_secret = "<yourAccessKeySecret>";
const char *bucket_name = "<yourBucketName>";
const char *object_name = "<yourObjectName>";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Use a char* string to initialize aos_string_t. */
    aos_str_set(&options->config->endpoint, endpoint);
    aos_str_set(&options->config->access_key_id, access_key_id);
    aos_str_set(&options->config->access_key_secret, access_key_secret);
    /* Specify whether to use CNAME. A value of 0 indicates that CNAME is not used. */
    options->config->is_cname = 0;
    /* Configure network parameters such as timeout periods. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int main(int argc, char *argv[])
{
    /* Call the aos_http_io_initialize method in main() to initialize global resources such as networks and memory. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Create a memory pool to manage memory. aos_pool_t is equivalent to apr_pool_t. The code to create a memory pool is included in the APR library. */
    aos_pool_t *pool;
    /* Create a memory pool. The second parameter is NULL. This value indicates that the pool does not inherit any other memory pool. */
    aos_pool_create(&pool, NULL);
    /* Create and initialize options. This parameter specifies global configuration information such as endpoint, access_key_id, acces_key_secret, is_cname, and curl. */
    oss_request_options_t *oss_client_options;
    /* Allocate the memory resources in the memory pool to the options. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize oss_client_options. */
    init_options(oss_client_options);
    /* Initialize the parameters. */
    aos_string_t bucket;
    aos_string_t object;
    aos_string_t file;
    aos_table_t *headers = NULL;
    aos_table_t *params = NULL;
    aos_table_t *resp_headers = NULL;
    aos_status_t *resp_status = NULL;
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    /* Specify the image style. */
    params = aos_table_make(pool, 1);
    apr_table_set(params, OSS_PROCESS, "style/<yourCustomStyleName>");
    /* Download the processed image to your local computer. */
    aos_str_set(&file, "<LocalFileName>");
    resp_status = oss_get_object_to_file(oss_client_options, &bucket, &object, headers, params, &file, &resp_headers);
    if (aos_status_is_ok(resp_status)) {
        printf("get object to file succeeded\n");
    } else {
        printf("get object to file failed\n");  
    }
    /* Release the memory pool, which releases memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Use the RESTful API

If your business requires a high level of customization, you can directly call RESTful APIs. To directly call an API, you must include the signature calculation in your code.

You can add IMG parameters or image style parameters to GetObject requests to process images. For more information, see GetObject.

  • Configure IMG parameters

    Sample requests:

    GET /oss.jpg?x-oss-process=image/resize,w_100 HTTP/1.1
    Host: oss-example.oss-cn-hangzhou.aliyuncs.com
    Date: Fri, 28 Oct 2022 06:40:10 GMT
    Authorization: OSS qn6qrrqxo2oawuk53otf****:UNQDb7GapEgJkcde6OhZ9J****
  • Add image style parameters

    Sample requests:

    GET /oss.jpg?x-oss-process=style/styleexample HTTP/1.1
    Host: oss-example.oss-cn-hangzhou.aliyuncs.com
    Date: Fri, 28 Oct 2022 06:40:10 GMT
    Authorization: OSS qn6qrrawuk53oqxo2otf****:UNapEgQDb7GJkcde6OhZ9J****

References

By default, IMG does not save processed images. However, OSS allows you to add the saveas parameter to an IMG request to save a processed image to a specified bucket as an object. For more information, see Save processed images.