As it becomes easier to create AMIs, you may find you end up with more than you need!

AMIs are made up of EC2 snapshots, which are stored in S3. There is a cost associated with storing snapshots, so you will want to clean them up periodically. Given the size of most AMIs (usually a few GBs), it is unlikely to be one of your major costs.

An even greater cost is the administrative overhead of managing too many AMIs. As your images improve and fixes are applied (especially security fixes), you may want to prevent people from using them.

To remove an AMI, you must first deregister it and then remove the underlying snapshots.

You can easily deregister snapshots through the web console or using the AWS CLI tool.

Once an AMI is no longer registered, you can remove the associated snapshots. Packer automatically adds the AMI ID to the snapshot's description. By searching your snapshots for the deregistered AMI ID, you can find which ones need to be deleted.

You will not be able to delete snapshots if the AMI has not been deregistered, or if deregistration is still taking place (it can take a few minutes).