What is Docker Registry?
A Registry is a place where docker images are present for example Docker Hub . Docker Hub is a Image Registry where Docker Images are Present . Docker users can pull Images from Docker hub and push or upload their own custom images to the Docker hub.
To understand more well docker registry we can take a example of Repository , a Yum server repository or any other linux package repository .
In that Repository all packages are present . what the end user does is . just run commands like yum install or apt-get install and that package is first downloaded from that particular repository and then installed . Similarly here in docker the end user runs commands like docker run or docker pull to pull or download images from the docker registry i.e (docker hub).
Here , In the above figure user tom , dave , harry are pulling images from the Image registry ( i.e. docker hub ) using the docker command docker pull.