digiKam - Professional Photo Management with the Power of Open Source
VisiPics - VisiPics does more than just look for identical files, it goes beyond checksums to look for similar...
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
dupeGuru - dupeGuru is a tool for finding duplicate files on your computer.
Photos on macOS - Photos keeps your images organized and accessible. Rediscover favorite shots with Memories. Access them on your devices with iCloud Photos.
Duplicate Cleaner - Duplicate Cleaner: the fastest and most popular tool for finding duplicate files. Over 1 million downloads: Get your copy now! Free and Pro versions available.