An Amazon Machine Image (AMI) in Amazon Web Services is a pre-configured template used to quickly launch and manage virtual machines (EC2 instances). It includes important components like the operating system, application software, and required configurations, allowing teams to create identical environments easily. There are different types of AMIs, such as public, private, and shared, depending on who can access them. Developers and DevOps teams use AMIs to ensure consistency across environments, enable fast deployments, simplify scaling, and manage version control of system setups, making cloud operations more efficient and reliable.