For those of us Mac users that don't keep every photo in the Photos app, we recently came across wonderful program that helps you quickly and efficiently de-duplicate photos on your hard drive. By simply dragging and dropping a folder from your mac into the program, PhotoSweeper will compare based on numerous criteria including file size, dimensions, date of creation and many more. One the analysis is complete, you can go photo by photo and mark those that you want to delete. When you're done, simply hit the trash button and they are gone. Like magic, but with some work from you. Learn more on the PhotoSweeper homepage.