What is the difference between save and export in Docker?

Question

I am playing around with Docker for a couple of days and I already made some images (which was really fun!). Now I want to persist my work and came to the save and

Answer 1

export: container (filesystem)->image tar.
import: exported image tar-> image. Only one layer.

save: image-> image tar.
load: saved image tar->image. All layers will be recovered.

From Docker in Action, Second Edition p190.

Layered images maintain the history of the image, container-creation metadata, and old files that might have been deleted or overridden.

Flattened images contain only the current set of files on the filesystem.