Duplicate photos accumulate quietly. You AirDrop a picture to yourself, save the same image twice from a chat, export a resized copy for something, and hold the shutter for a second too long. None of it feels like a decision. Months later it is a few hundred files.
Try the built-in Duplicates album first
Photos has had duplicate detection since iOS 16. Open Photos, go to Albums, scroll to the Utilities section, and look for Duplicates. If you do not see it, your library has none that it recognizes, or it has not finished indexing.
That indexing matters. Photos does the work in the background while the phone is locked and charging, so on a large library the album can take a day or more to appear and to fill in. Merge is the useful button: it keeps the highest quality version and combines the metadata from the copies rather than making you pick.
Why some copies never show up there
The built-in album is conservative by design. It is looking for genuine duplicates, so it tends to skip:
- Resized or re-exported copies. Same picture, different dimensions or file size.
- Images re-saved through another app. A photo that made a round trip through a messaging app comes back re-encoded and is no longer byte-identical.
- Near matches. A small crop, a filter, a slight color correction.
- Burst runs. Eleven frames of the same jump, all technically different photos.
Those are the categories where the space actually hides, because they are the ones nobody prunes by hand.
How Unfill groups copies
Unfill compares media by content, on the device, and sorts what it finds into four kinds of group so you know how much scrutiny each one needs:
- Exact. Byte-equivalent copies with the same dimensions and file size. AirDrop, re-import, re-save. Safe to select in bulk.
- Similar. The same image content at a different size or after a re-encode.
- Near. Visually close but not identical. A minor crop, a color tweak, a light recompression.
- Burst frames. A run of shots from one moment, offered as a set so you can keep the best and bin the rest.
The comparison happens locally. No image, thumbnail, filename, or identifier is uploaded to do it.
Reviewing without losing the good one
The failure mode of duplicate cleanup is keeping the wrong copy. A few habits prevent it:
- Prefer the largest file in a group. It is usually the original rather than the re-save.
- Check the dates. The oldest item in a group is often the one your albums and memories are built around.
- Watch for edits. A smaller file can be the version you actually cropped and adjusted, and that one is the keeper.
- Handle exact groups in bulk and near groups with your eyes. The tiers exist so you can spend attention where it matters.
Unfill preselects nothing you have not seen and deletes nothing on its own. The optional assistant can suggest opening the duplicate finder or a particular group, using only aggregate counts and byte totals, and it cannot delete anything itself.
Duplicates are rarely the biggest win
This is worth saying plainly. Unless you have been importing the same camera roll repeatedly, duplicates usually free less than people hope. Burst runs and long video are typically worth more. Clearing duplicates is still satisfying and still worth doing, but if you came here because your phone is full, start with what is actually taking up space, then decide whether to compress or delete.
Unfill is coming to the App Store.