# Pushing an image to a public repository in Amazon ECR public
Pushing an image

You can push your Docker images to an Amazon ECR public repository with the **docker push** command.

**Important**  
Amazon ECR requires that users have permission to make calls to the `ecr-public:GetAuthorizationToken` and `sts:GetServiceBearerToken` API through an IAM policy before they can authenticate to a registry and push any images to an Amazon ECR repository.

Amazon ECR Public also supports creating and pushing Docker manifest lists which are used for multi-architecture images. Each image referenced in a manifest list must already be pushed to your repository. For more information, see [Pushing a multi-architecture image to a public repository in Amazon ECR public](docker-push-multi-architecture-image.md).

**To push a Docker image to an Amazon ECR public repository**

1. Authenticate your Docker client to the Amazon ECR public registry to which you intend to push your image. Authentication tokens are valid for 12 hours. For more information, see [Registry authentication in Amazon ECR public](public-registry-auth.md).

1. If your public repository does not exist in the registry you intend to push to yet, create it. For more information, see [Creating an Amazon ECR public repository to store images](public-repository-create.md).

1. Identify the image to push. Run the **docker images** command to list the images on your system.

   ```
   docker images
   ```

   You can identify an image with the *repository:tag* value or the image ID in the resulting command output.

1. <a name="image-tag-step"></a>Tag your image with the Amazon ECR public registry, public repository, and optional image tag name combination to use. The public registry format is `public.ecr.aws/registry_alias`. The public repository name should match the repository that you created for your image. If you omit the image tag, we assume that the tag is `latest`.

   ```
   docker tag e9ae3c220b23 public.ecr.aws/registry_alias/my-web-app:image-tag
   ```

   For this example command, note the following:
   + Image ID is *e9ae3c220b23*
   + Public registry is `public.ecr.aws/registry_alias/`
   + Repository is *my-web-app*
   + Image tag is *image-tag*

1. <a name="image-push-step"></a>Push the image using the **docker push** command (again, (`my-web-app` is the name of the repository, and *image-tag* is the image tag):

   ```
   docker push public.ecr.aws/registry_alias/my-web-app:image-tag
   ```

1. (Optional) Apply any additional tags to your image and push those tags to Amazon ECR Public by repeating [Step 4](#image-tag-step) and [Step 5](#image-push-step). You can apply up to 1000 tags per image in Amazon ECR Public.