Ok, this is going to sound like an ad....but it's not...It's advice:
This software:PhotoRescue just saved my bacon. I was downloading images from my camera card using Picasa, and something went wrong/funny. I had 497 photos, but I only got 380 or so photos, but it erased them all from the card anyway, as if it were done downloading. The missing photos included some family vacation photos, and I was understandably pissed off. I tried several packages to recover lost files, but each one ended up recovering corrupt jpg files, and I even tried jpg restoration software, which showed me the recovered files weren't even the right ones, much less complete images.
PhotoRescue worked - and by worked, I mean, it recovered the files, the CORRECT files, and they were images - the images I expected them to be, and it worked beautifully, giving me images to select from as to what I wanted restored (so I didn't have to restore the movie files and 380 photos I already had downloaded). The software was $29, a price I was glad to pay once I saw that the software did what I needed it to do. After trying about 5 or 6 other packages, I was happy to finally have something that worked.