Docker image contains a many files packaged, ready to run as a application. This contains all the dependencies such as configuration, source code compilation, binaries, plugins or any that required to run it.

The files in the image can not be modified and readonly.

if you want to modify the image files, you can modify by adding layer.

That means docker images are made of many layers where each layer contains new changes to files.

you can use below command to display the image history changes

docker image history

Docker architecture allows you to use layer to provide an flexibility and reuse an images ,

It contains parent and child images. where child image is also called base images.

List all images in docker

docker images

Show images by name and tag

docker image -a