Pixiple - Find images similar in pixel and/or metadata content
ImageDupeless - ImageDupeless - the program for search/find of the similar images (duplicates) in the large galleries (collections).
Awesome Duplicate Photo Finder - Awesome Duplicate Photo Finder is a free powerful tool, that helps you to find and remove duplicate...
VisiPics - VisiPics does more than just look for identical files, it goes beyond checksums to look for similar...
dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
AntiDupl - AntiDupl.NET can find and display duplicate images in the main graphic formats: JPEG, GIF, TIFF...