Well I started this project before you mentioned this, I naively I just asked IrfanView to load all 365,000 files from my top directory down. So far it's up to 101,000 and hasn't slowed down. If I visually inspect the thumbnails in bulk, I think I can spot any corrupted images pretty quick. Or maybe IrfanView will refuse to load a corrupted image. Either way I should be able to identify any problematic files. Right?
I have a mix of file types; NEF, JPG, DNG, TIFF, PSD, RAF, and others.