This post is preceded by a public service announcement to back up all important data, often. (So far it seems the best way to back up photos is to get them printed/developed).
Had a scare with a half gig compact flash card acting up on me, that contained photo documentary of my daughter's birthday. Enter Gentoo Wiki to the rescue. (Note that this site contains information that could be useful for other distributions as well, like say fedora or ubuntu....).
Here's a nice link explaining different steps to take to recover photos. A few notes, are that:
dosfsk
runs in place (seems obvious), but when I have a wacked out drive/partition, I really want to copy it (using dd or something) and work on the copy, not on the original.
Anyway, dosfsk claimed to fix/rename a bunch of files. Then I started trying to use
jpg-recover
I had issues with it (it's slow and it seemed to hang my computer). Plus I don't think just recovering jpg's is sufficient these days, when you have cameras that now double as camcorders.
So here's the most useful advice. Use PhotoRec which also recovers movies. It uses a (semi-confusing) wizard interface. The User guide walks one through the steps. The most confusing issue was selecting the partition table (what is an Intel partition?). The Canon (fat16?) format was recognized when I selected "None" as the partition table type, but not when I tried Intel partition. After that it ran (really quickly) and recovered most/all of the files.
The homepage of photorec says that it runs on windows and macs too. So if you find yourself in need check it out!