Amazon Machine Images (AMIs)

Amazon Machine Images (AMIs) can be used to configure AWS EC2 instances. This would allow you to bypass the operating systems installation and configuration. When you request an AWS EC2 instance, you can select from one of the preconfigured AMIs to be used in the EC2 instance. 

You can also save an AMI from an existing EC2 instance. For example, after you configure an EC2 instance specific to your needs, you can save an image of it as an AMI for future use or sharing with other users.

Amazon Machine Images

This link provides more about the AWS machine images, using and creating your own AMI, and other capabilities: