DoublePics is a tool with which pictures may be detected if they exist more than once (or in similar versions) on a computer system or network.
It does not matter if these pictures have - different sizes - different contrast, color or gamma values - different file formats.
The program's built-in fuzzy logic with its adjustable sensitivity or tolerance allows you to detect - both pictures which are practically identical - and pictures which are somehow related, have been retouched, cut differently or otherwise modified (e.g. by adding logos).
Additionally, the Enterprise Edition is capable to distribute the load on multiple machines.
Find and delete duplicate pics.
Find duplicate files.
Free Similar Image Finder
Delete Duplicate Images (Microsoft Advises)
Delete Duplicate Pictures (Microsoft Advises)