In this scenario, we'll understand about layers in docker image.
Docker Images and Layers
Layers in docker image
Each Docker image references a list of read-only layers that represent filesystem differences.
Layers are stacked on top of each other to form a base for a container's root filesystem.
debian image to your local system.
docker pull debian.
docker history debian shows you list of layers that
More Information you can find out with:
docker inspect debian