Image duplicate finder

So, I have a lot of pictures (thank you /b/).

Now, I need some sort of finder to be able to look for image duplicates while checking multiple subdirectories, and one that can handle a lot of files.

Now, I have GQview, but loading more than a couple hundred pictures crashes it, and it can't check subdirs.

Anyone have any good and free apps?

dup detector is one i found a while back. donno how good it is though.

I like DupDetector best

I've used DupDetector with directories containing over 200,000 files (with subdirectories).  It's good and pretty fast.