Starting now, Amazon EC2 adds service quotas for Amazon Machine Images (AMIs) in the AWS GovCloud (US) Regions. You will see three new quotas in the EC2 section on the Service Quotas console page. The first quota is for the total number of AMIs within your AWS account, the second quota is for the total number of public AMIs within your AWS account, and the third quota is on the number of shares you can have for each AMI. These quotas are added by default for all AWS accounts and do not require any action from you. Each quota is per AWS account per AWS Region.
Source:: Amazon AWS