dupeGuru is a free and open source tool to find duplicate files on your computer. It can scan either filenames or contents. The filename scan features a fuzzy matching algorithm that can find duplicate filenames even when they are not exactly the same.
AntiDupl.NET can find and display duplicate images in the main graphic formats: JPEG, GIF, TIFF, BMP and PNG. The comparison is based on the contents of the files, so the program can find not only almost identical, but similar images.
VisiPics does more than just look for identical files, it goes beyond checksums to look for similar pictures and does it all with a simple user interface. First, you select the root folder or folders to find and catalogue all of your pictures.Discontinued
The program seems to be no longer updated. Last version, 1.31, released in February 2013, can be still downloaded from the official website.
Pixiple searches your files for images that are similar in pixel and/or metadata content and presents you with a sorted list of similar image pairs to compare and manipulate. Pixiple is open source, no-nonsense, unrestricted and completely free.
Awesome Duplicate Photo Finder is a free powerful tool, that helps you to find and remove duplicate photos on your PC. With this program you can easily clean up your photo collection from duplicates or even similar images.
Anti-Twin is a small software application which compares files, i.e. it searches for duplicate or similar files on your hard disk drive. All similar or identical files that were found can either be sent to the recycle bin or directly deleted.Discontinued
Last version 1.8d from 2010, see http://www.joerg-rosenthal.com/en/antitwin/
Visual Similarity Duplicate Image Finder will find fast all similar and duplicate pictures and photos in a folder and its sub folders. Visual Similarity Duplicate Image Finder uses advanced algorithms to find duplicate photos in a way that a human does.
Image Comparator is an easy tool that finds duplicate image files in your system. In order to do that it scans your images pixel by pixel; therefore even if two images have different formats and file sizes (MB/KB) Image Comparator finds them.Discontinued
The program is no longer updated. Last version, 1.7.3, released in April 2014, can be still downloaded from SourceForge.
Tidy Up is the duplicate finder and disk tidiness utility for expert users. It's the only fully-featured duplicate remover available on the market, and allows you to efficiently clean your computer from the junk it built-up.