An Elastic Compute Service (ECS) image provides the information that is required to create an ECS instance. You must specify an image when you create an ECS instance. An image is a copy of data from one or more disks. An instance image can contain data from only the system disk or from both the system disk and data disks.
Image types
ECS images are classified into the following categories based on the entity that manages the images: public images, custom images, shared images, community images, and Alibaba Cloud Marketplace images. 
Image type | Description | Technical support | References |
Public images | Public images provided by Alibaba Cloud are licensed images that are thoroughly tested to ensure security and stability. Public images for Windows Server operating systems and mainstream Linux operating systems are provided. |
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Custom images | Custom images are created from instances or snapshots or are imported from your computer. | For custom images that are derived from public images, Alibaba Cloud provides the same technical support that is provided for public images. For imported images:
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Shared images | Shared images are shared to you by other Alibaba Cloud accounts. | Alibaba Cloud does not provide technical support. Contact the accounts that shared the images for technical support. | |
Alibaba Cloud Marketplace images | Alibaba Cloud Marketplace images contain operating systems and pre-installed software and are thoroughly tested by the providers to ensure security and stability. Alibaba Cloud Marketplace images are classified into the following types based on the provider:
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Community images | Community images are published by Alibaba Cloud users for public use. | Alibaba Cloud does not provide technical support. |
The preceding information, which is described in the Technical support column, is valid only before the end of life (EOL) of images. For information about how to obtain technical support after the EOL of an image, see Maintenance support for operating systems.
Alibaba Cloud provides release notes for public images to introduce new features and security patches of operating systems. For more information, see Release notes. Alibaba Cloud also synchronizes new features and security patches from open source communities and operating system vendors to Alibaba Open Source Image Site. You can obtain new features and install security patches based on your business requirements.
Alibaba Cloud helps you ensure cloud security. Alibaba Cloud ensures the security of the cloud platform, including the security of the hardware, software, and network. You are responsible for not introducing security risks to your ECS instances. You must properly manage operating systems, such as installing updates and security patches, installing secure applications and tools on the instances, and configuring security groups that Alibaba Cloud provides. For more information, see Best security practices.
Image prices
You may be charged for using images. The following table describes the billing methods for different image types.
Image type | Billing rule |
Public images | Public images, including open-source and commercial public images, are provided by Alibaba Cloud at different prices:
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Custom images | Custom images are created from instances or snapshots or imported from your computer. Billing for custom images consists of two parts:
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Shared images | Shared images are shared with you by other Alibaba Cloud accounts. If you use a shared image that is derived from a paid image, you are charged a license fee for the shared image. For example, if you share Image A (paid image) with User B and User B uses Image A to create instances, User B is charged a license fee for Image A. |
Alibaba Cloud Marketplace Images | Alibaba Cloud Marketplace images are provided by independent software vendors (ISVs). Their prices are displayed on the image product pages in Alibaba Cloud Marketplace. |
Community images | Community images are custom images shared by users with the Alibaba Cloud community. If a community image is derived from a paid image, you are charged a license fee when you use the community image to create ECS instances. |
For more information, see Images and the "FAQ about the commercial availability of images" section of the Image FAQ topic.
Select and search for images
You can select an image based on the region, image type, image price, operating system, and built-in software. For more information, see Select an image.
You can search for an image based on the type, name, ID, and ID of the snapshot from which the image is created. Then, you can use the image to create instances or perform other operations. For more information, see Find an image.
Replace the image of an instance
After you create an instance, you can replace the operating system of the instance by replacing the system disk of the instance. For more information, see Replace the operating system of an instance.
Limits
For information about the limits and quotas of images, see the "Image limits" section of the Limits topic.
API operations
You can call API operations to manage images. For more information, see the "Images" section of the List of operations by function topic.