Currently, the most commonly adopted way to store and deliver Docker images is through Docker Registry, an open source application by Docker that hosts Docker repositories. This application can be deployed on-premises, as well as used as a service from multiple providers, such as Docker Hub, Quay.io, and AWS ECR.
The application is a simple, stateless service, where most of the maintenance work involves making sure that storage is available, safe, and secure. As any seasoned system administrator knows, that is far from an easy ordeal, especially, if there is a large data store. For that reason, and especially if you're just starting out, it is highly recommended to use a hosted solution and let someone else deal with keeping your images safe and readily available.
ECR is AWS's approach to a hosted Docker registry, where there's one registry...
