Photos creates cache files almost every time you work with it. Here’s an example. If you have iCloud Photo Library enabled, all your pics are stored in the cloud. But when you view these pics on your Mac, Photos creates locally cached copies of them. So, even if you keep all photos in iCloud, their local copies are still wasting space on your Mac.

More cache files pile up when Photos detects faces on your pics — that is, every time you add photos of people. If you import new pics often, you’ve probably got a lot to clean up.

When you import RAW files into Photos, the app creates JPEG copies of them. These JPEGs are what you see in Photos — and heavy RAWs just sit on your Mac, forgotten. If you no longer need the RAW originals, CleanMyMac will remove them to save you gigabytes of space.* But don’t worry: it will always ask you first.

This feature is not yet available on macOS High Sierra.

Just like the Photos app, iPhoto has tons of junk hidden in its library. It’s a whole different kind of junk, and CleanMyMac cleans it up, too. Photo Junk searches your iPhoto library to locate useless and hidden copies of your pics, kept by iPhoto after you rotate, crop, or otherwise edit them.