An Amazon Machine Image (AMI) is an encrypted machine image that contains all information necessary to boot instances of your software. For example, an AMI might contain Linux, Apache, and your web site or it might contain Linux, Hadoop, and a custom application.

AMIs are stored in Amazon S3.

Public AMIs are made available by Amazon and the Amazon EC2 community and can be downloaded from the Resource Center. You can use public AMIs as a base to create your own custom private AMIs.

Private AMIs are AMIs that you own and can only be accessed by you or those to whom you grant access.

Paid AMIs are AMIs that you purchase from developers or AMIs that come with service contracts from organization such as Red Hat.

After an AMI is launched, the resulting running system is called an instance. By default, you can run up to 20 instances. If you need more than 20 instances, please complete the Amazon EC2 Instance Request Form and your request will be considered.

Instances remain running unless they fail or are terminated. When this happens, the data on the instance is no longer available.

The instance store refers to the disk storage associated with an instance. In the event an instance fails or is terminated, all content on the instance store is deleted.