How to prevent Git from compressing certain files?

Hi,

I'm (ab)using Git to store my media files, i.e. digicam pictures (*.jpg) and the like. This way I can e.g. comment a series of pictures without installing and learning a special purpose "Photo Archiving" tool. Gitk shows the roadmap!

Somewhere I read that Git isn't supposed to efficiently handle binary files. Of course, I don't want to merge my files, just store them with their history and git-push them to some "safe place".

I figured that pushing and git gc'ing both try to compress those files (or differences) really hard. Works great for "regular" files, but is pointless with jpegs.

Question: Is there a way to prevent Git from trying to compress certain
files based on their extension?

-- Dirk