Let's download our first image by typing docker pull mongo. This will download the image from the mongo repository. By default, docker pulls images from docker hub.
You can visit hub.docker.com to search through a list of available images. If no tag is provided, docker pulls images with the latest tag. Download a specific version of a docker image by appending a colon with a tag, or version to the end of the image name.
Let's download another image. Note that official docker images only have one name, while community submitted images are name spaced with a user name, and a slash. Let's see which images are downloaded into our machine by typing docker images.
We can see the images along with the tag, image ID, when they were created, and the size. To remove an image, type docker rmi, and then, the image name. You can also remove a specific tag by appending it to the image name.
Another way to remove an image is by the image ID. Note that you don't need to use the full ID, but just the first few letters as long as it has uniqueness between the other downloaded image IDs.