As mentioned earlier, a Docker image is a way to deliver applications. You can create a Docker image and share it with other users using a public/private registry service. A registry is a stateless, highly scalable server-side application which you can use to store and download Docker images. Docker registry is an open source project, under the permissive Apache license. Once the image is available on a Docker registry service, another user can download it by pulling the image and can use this image to create new Docker images or run containers from this image.