Overview - Object Storage Service - Alibaba Cloud Documentation Center

You can specify Image Processing (IMG) parameters in GetObject requests to process image objects in Object Storage Service (OSS). For example, you can add image watermarks to images or convert image formats.

IMG parameters

OSS allows you to use one or more parameters to process images. You can also specify multiple IMG parameters in a style to process images at a time. For more information about image styles, see Image styles.

If you specify multiple IMG parameters, OSS processes the image in the order of the parameters. The following table describes IMG parameters.


IMG	Parameter	Description
Resize images	resize	Resizes images.
Add watermarks	watermark	Adds image watermarks or text watermarks to images.
Custom crop	crop	Crops rectangular images based on the specified size.
Adjust image quality	quality	Adjusts the quality of images in the JPG format and WebP format.
Convert image formats	format	Converts the formats of images to specified formats.
Query the EXIF data of an image	info	Obtains image information, including basic information and Exchangeable Image File Format (EXIF) information.
Auto-rotate	auto-orient	Auto-rotates images for which the auto-orient parameter is configured.
Circle crop	circle	Crops images into circles of the specified size based on the center point of images.
Indexed slice	indexcrop	Crops images along the specified horizontal axis or vertical axis and selects one of the images.
Rounded rectangle	rounded-corners	Crops images into rounded rectangles based on the specified rounded radius size.
Blur	blur	Blurs images.
Rotate	rotate	Rotates images clockwise by a specified angle.
Gradual display	interlace	Configures gradual display for JPG images.
Query the average tone	average-hue	Queries the average hue of images.
Brightness	bright	Adjusts the brightness of images.
Sharpen	sharpen	Sharpens images.
Contrast	contrast	Adjusts the contrast of images.

For example, if you add the resize and quality parameters to process the example.jpg image, the URL of the image is https://image-demo.oss-cn-hangzhou.aliyuncs.com/example.jpg?x-oss-process=image/resize,w_300/quality,q_90. You can configure CDN back-to-origin rules to filter out or retain the IMG parameters contained in the URLs of images that you want to retrieve. This way, you can retrieve source images or images that are processed by using IMG parameters.

Retrieve source images
You can enable the parameter filtering feature of CDN to filter out all parameters that follow the question mark (?) in the URL of the image that you want to retrieve. In this example, the example.jpg source image is retrieved.
Retrieve processed images
You can enable the parameter retaining feature of CDN to retain all parameters that follow the question mark (?) in the URL of the image that you want to retrieve. In this example, the processed image is retrieved.

For more information about how to configure CDN back-to-origin rules, see Ignore parameters.

IMG methods

You can use object URLs, API operations, and SDKs to process images. For more information, see IMG implementation modes.

Limits


Item	Description
Image formats	Only JPG, PNG, BMP, GIF, WebP, TIFF, HEIC, and AVIF images are supported. Only resizing, cropping, rotation, and image watermarks are supported for dynamic images such as GIF images. If you want to encode or decode dynamic images in the WebP format, submit a ticket.
Image size	The size of a source image cannot exceed 20 MB.
Image width and height	For the rotate operation, the height or width of the source image cannot exceed 4,096 pixels. For other operations, the width or height of the source image cannot exceed 30,000 pixels, and the total pixel number of the source image cannot exceed 250 million. The total pixel number of a dynamic image, such as a GIF image, is calculated based on the following formula: `Width × Height × Number of image frames`. The total pixel number of a static image, such as a PNG image, is calculated based on the following formula: `Width × Height`.
Image compression	The width or height of a compressed image cannot exceed 16,384 pixels. The total pixel number of a compressed image cannot exceed 16,777,216.
Advanced image compression	The number of pixels of a compressed HEIC image cannot exceed 4,096 × 4,096. The number of pixels of a compressed AVIF image cannot exceed 4,096 × 2,304.
Image styles	You can create up to 50 image styles for a bucket. If your business requires more than 50 styles for a bucket, submit a ticket.

Billing

You are charged the following fees when you use IMG:

API operation calling fees
A GetObject request is generated each time you use IMG to process an image. You are charged based on the number of generated requests. For more information about API operation calling fees, see API operation calling fees.
Traffic fees
You are charged for the outbound traffic over the Internet based on the size of the processed images. For more information about traffic fees, see Traffic fees.

IMG versions

IMG provides two versions of API operations. This topic describes the new version of the API operations. Update support is no longer provided for the old version. For more information about the compatibility between the new and old versions of API operations, see FAQ on using old and new versions of APIs and domain names.