One important part of Docker's popularity is its community and the ease with which you can share, find, and extend Docker images. The central place for this is the Docker Registry Hub that can be found at https://hub.docker.com/.
Here, we can search and, in many ways, browse for image repositories to find exactly what we're after. If we take a look at the popular ones, we will see what others are using the most.
If we click on the Ubuntu repository, we will see lots of information about the image, the tags that are available, users' comments, the number of stars it has, and when it was updated.
The screenshot is displayed as follows:
If we click on a tag in the main view, we'll see something called the Dockerfile. This is the image description that runs when an image is being created. Further in this book, we'll write our own.
If you're interested in an image in the Docker hub, I recommend that you read the Information/README as well as the other users...