FreeRecover is a tiny, portable open-source file recover tool.
The program comes in the form of a single, 240KB executable, so it's easy to run from any USB key. And it couldn't be much simpler to operate: launch the file, choose your drive (which has to be NTFS), click Search and wait to see what it finds. (Although you won't be waiting long - scan times seem very fast).
FreeRecover will then probably present you with an extremely lengthy list of deleted files. You can search by all of a part of the file's name, though, which should cut the report down to a more manageable size.
If you're browsing for images, then clicking one of them will display the results in a preview window, helping you to correctly identify the lost file.
And if you're in luck, just check the boxes to the left of every file you'd like to undelete, click Recover File, and choose where you'd like to save them (which, ideally, should be on a different drive to avoid overwriting anything, although the program doesn't enforce this).
This is all fairly basic. There's no support for recovery from FAT-based drives, for instance. There's no "deep scan", no way to track down lost files by scanning drive space. File preview options are limited, and you can't search the list of undeleted files by anything other than name.
Often the basics are enough, though, and there's no doubt that FreeRecover makes simple undelete tasks quick and easy. It just might be worth including in your portable troubleshooting toolkit.