Duplicate files · Duplicates basics
Does Storage Studio find similar photos, or only exact copies?
Short answer: Only exact copies. Storage Studio groups files whose content is identical, so resized, edited or re-exported versions, burst shots and the same song in another format are treated as different files and never offered for removal.
Only exact copies. The Duplicates window groups files whose content is identical, so a photo and a resized, cropped, edited or re-exported version of it are treated as different files — and so are burst shots, screenshots of the same thing, or the same song saved in two formats.
That's deliberate: an exact copy can be removed without losing anything, while "similar" files often differ in ways that matter to you.
If you keep your pictures in the Photos app, Photos has its own tool for this — see duplicate photos in the Photos library.