images

Images are made up of multiple layers that get stacked on top of each other and represented as a single object. Inside of the image is a cut-down operating system (OS) and all of the files and dependencies required to run an application. Because containers are intended to be fast and lightweight, images tend to be small.
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docker

docker image pull

is the command to download images

docker image pull ubuntu:latest
docker image list

lists all of the images stored in your Docker host’s local cache. To see the SHA256 digests of images add the --digests flag
docker image inspect

gives you all of the glorious details of an image — layer data and metadata
docker image rm

is the command to delete images. You cannot delete an image that is associated with a container in the running (Up) or stopped (Exited) states

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