How to delete duplicate photos
Guides · Photos · Updated
A ten-year-old photo library commonly contains 20 to 30% duplicates. They come from stacked backups, repeated phone exports, and photos received by message and saved again. The real challenge is not finding them: it is deleting them without making a mistake.
Three kinds of duplicates, three treatments
An exact duplicate is the same file copied twice: same content, same size. It is the only case where deleting is completely risk-free.
A re-encoded duplicate is the same photo passed through a messaging app or social network: visually identical, but a different file, often of lower quality. Here, keep the heaviest version.
A near-duplicate, finally, is a burst: three shots of the same scene a second apart. No tool can choose for you which one to keep.
Spot duplicates without special software
Start with the simplest clue: the name. Suffixes like (1), (2), - Copy or _copy signal copies created by the system during a move. Sorting by name in File Explorer or Finder groups them instantly.
Sorting by size works just as well: two files with exactly the same size, down to the byte, are almost always the same file. Sort the details view by “Size” and scan the blocks of repeated values.
The careful method, in four steps
Never delete right away. The idea is to gather everything first, make duplicates visible, and only decide once you have the full picture in front of you.
- Gather all your photo sources into a single ZIP archive
- Organize it by date: duplicates necessarily land in the same monthly folder
- Trifouille adds a suffix to files with the same name, “photo (2).jpg”, instead of overwriting them
- Go through month by month and delete with full knowledge
Why sorting by date helps so much
As long as your photos are spread across five backup folders, two copies of the same picture never meet. You cannot compare what you cannot see side by side.
Once everything is gathered in a year / month tree, each duplicate mechanically ends up next to its twin. Comparing becomes visual and quick, and what used to be a vague project becomes an hour of concrete work.
Free duplicate finders
For large volumes, a dedicated tool saves a considerable amount of time. dupeGuru and Czkawka, both free and open source, find exact duplicates by content fingerprint, and can also detect visually similar images, even resized or recompressed.
They delete nothing without your approval: they present groups of similar files and let you choose. Use them on a working copy, and never on your only backup.
In Photos on iPhone and Mac
Since iOS 16 and macOS Ventura, the Photos app shows a “Duplicates” album under Utilities. It groups identical or near-identical images there, and offers to merge them while keeping the best quality and the most complete metadata.
It is the simplest method if your whole library already lives in Photos. It cannot see copies stored elsewhere, though: external drives, ZIP archives, old backup folders.
The safety rule
Keep the original archive until the cleanup is finished and checked. As long as it exists somewhere, no deletion mistake is permanent.
And never delete from your one and only copy. A deduplication run directly on the only copy of ten years of photos is the scenario that ends badly.
Frequently asked questions
Are two files with the same name necessarily identical?
No, and that is exactly the trap. Two different cameras both produce IMG_0001.JPG files that have nothing to do with each other. Always compare size and date before deleting.
Should I keep the heaviest version?
Almost always, for the same image: the larger file is the least recompressed version, and therefore the best quality.
Do duplicate photos really take up much space?
Yes, more than you would think: a smartphone photo weighs 3 to 8 MB, and a 30,000-photo library with 25% duplicates easily wastes 30 GB.
More guides: Photos
For the big picture, start with How to sort photos by date automatically.