How can I deregister unused AMIs and delete snapshots from my account?

Resolution

Note: You can't deregister AMIs shared with you by an external AWS account. And, you can't delete EBS backup snapshots.

If you try to deregister a shared AMI, you receive an error similar to the following

Failed to deregister the AMI ami-xxxxx. API error: "Not authorized for image:ami- xxxxx"

You aren't billed for snapshots that another AWS account owns and shares with your account. You're billed only when you copy the shared snapshot to your account. You're also billed for EBS volumes that you create from the shared snapshot.

To identify rising costs of EBS snapshots, review the list of AMIs associated with your account in that AWS Region:

1. Open the Amazon Elastic Compute Cloud (Amazon EC2) console, and then select AMIs.
2. From the dropdown list, select Owned by me.
3. Choose the gear symbol in the upper-right corner.
4. Turn on the Product code option, and then select Confirm. This option filters for AMIs owned by the account and denotes AWS Marketplace AMIs in the Product code column.
5. Select the AMIs that you no longer need.
6. Select Actions, Deregister AMI.

Note: Deregistering an EBS-backed AMI doesn't affect any snapshots created for the instance's volumes when the AMI was created.