What is Docker Images and Explain in 10 bullet lines?

Collection of file systems, ROOTFS, APPFS, USERFS.
One copy of docker image can attach to many containers.
From one image multiple containers can be created
File system layered over each other.
Higher layer wins.
Each layer is each File system
Layer 0 should be base image or Root FS
Once image is attached to container, these layers will be attached to the container as a single layer
The layers in the image will be in read only format, and to have the changes the thin layer in container should be used and commit that and form a new image