Creating a very simple revision system for photos in python

[Thomas W]

I`m thinking about creating a very simple revision system for photos
in python, something like bazaar, mercurial or git, but for photos.
The problem is that handling large binary files compared to plain text
files are quite different. Has anybody done something like this or
have any thoughts about it, I`d be very grateful. If something like
mercurial or git could be used and/or extended/customized that would
be even better.

We are talking about large numbers of photos and some of them are
large in size as well, but the functionality does not have to be a
full fledged revision system, just handle checking out, checking in,
handling conflicts, rollbacks etc, preferrably without storing
complete copies of the files in question for every operation.

Thanks for any input. :-)