How to remove garbage crept between layers in docker images?

Question

Docker

After each commit, my image adds impressive megabytes.
Why is this happening?
There is no magic docker add command in docker (similar to git), absolutely everything is added to the commit.
How to be?

Answer 1

Because a lot of files have been changed. Here they are all going into a new image.
If you only need what you need - then as the official dock says - use Dockerfile