Define a docker image in 10 bullets points

Docker image image is the collection of file systems.
Each file system in image is known as layer.
Docker image can contain either single layer or multiple layers.
In case of multiple layes one layer is originated from prev layer.
Base file system(root) is the mandatory layer of the image.
One copy of image can mounted into each container.
All layers are meged into one layer before mounted to container.
Highest layered file gets priority to avoid conflicts at the time of merging.
Repo name can always same as image name.
Repo can be stored in registry.