The Photos library is taking up space on a Mac

What the package holds

In Finder the library looks like one file. It is a folder that Finder keeps closed, and right-clicking it → Show Package Contents shows what is inside:

• originals — every photo and video as it was imported. This is nearly all of the size.
• resources — what Photos makes from them: thumbnails, previews, the rendered version of every edit, and the faces, scenes and text it has recognised.
• database — the catalogue that ties it together: albums, edits, dates, places, which photo is which.

Look, but do not move or delete anything in there. Photos keeps the database and the files in step, and a file removed behind its back is a photo that shows as missing, or a library that will not open. To see the size:

du -sh ~/Pictures/Photos\ Library.photoslibrary

System Settings → General → Storage shows the same figure under Photos. Both count the edits and thumbnails as well as the originals, which is why the library is bigger than the camera roll it came from.

Free space from inside Photos

1. In Photos, delete the photos and videos you do not want. Videos, each the size of hundreds of photos, screenshots and bursts are where to start, and the sidebar's Media Types section has an album for each.
2. Open Recently Deleted in the sidebar and click Delete All. Until you do, nothing is freed: deleted items are kept for 30 days.
3. Check Photos → Settings → General → Importing. If Copy items to the Photos library is ticked, every photo you import from a folder or a card is copied, so the version in Downloads or on the card is a second copy you can remove.

Optimise Mac Storage

With iCloud Photos on, Photos → Settings → iCloud offers two choices. Download Originals to this Mac keeps the full library here. Optimise Mac Storagekeeps the full-size originals in iCloud and small versions on the Mac, fetching an original only when you open or edit it. For a library larger than the disk can comfortably hold, this is the setting that solves it.

Two things to know. It needs an iCloud plan with room for the whole library, because iCloud becomes the only full copy. And the space does not come back the moment you switch it on: macOS removes local originals as it needs the room, and counts them as purgeable in the meantime, so the Photos figure in Storage settings falls over days rather than at once.

Move the library to an external drive

If you want every original on your own disk but not on the Mac's, the whole package can live on an external drive. Photos works from it exactly as before, as long as the drive is connected.

1. Quit Photos.
2. Use a drive formatted as APFS or Mac OS Extended (Journaled), not exFAT or FAT, and not the drive Time Machine backs up to. Select it in Finder, press Command-I, and under Sharing & Permissions make sure Ignore ownership on this volume is ticked.
3. Drag Photos Library.photoslibrary from ~/Pictures to the drive and wait for the copy to finish. It is the size of the library, so it takes a while.
4. Hold the Option key while opening Photos, click Other Library, and choose the copy on the drive.
5. If you use iCloud Photos, open Photos → Settings → General and click Use as System Photo Library, so iCloud follows the library to its new home.
6. Once the moved library opens and everything is there, move the original in ~/Pictures to the Trash and empty it. That is the moment the space comes back.

Keep a backup of the drive: the library on it is now the only copy of your originals unless iCloud Photos has them too.

Duplicates and similar shots

Since macOS Ventura, Photos has a Duplicates album in the sidebar (below Utilities in current versions). Merge keeps one photo where the copies were and moves the others to Recently Deleted for 30 days. It does not look at bursts, re-takes or the five almost-identical photos of the same plate of food; for those, Folio Refresh, a separate Caddora app, scans the Photos library as well as folders for identical copies, similar shots and bursts, suggests the one to keep, and moves nothing until you approve it.

Why it grows back

Because the library is your photos, and you keep taking them. iCloud Photos brings every shot from the iPhone to the Mac; each edit adds a rendered copy; and Photos keeps rebuilding its thumbnails and analysis in resources. None of that is waste. Optimise Mac Storage is the setting that lets the library keep growing without the disk growing with it.

For duplicate files outside the Photos library, see how to find duplicate files on a Mac.

Where the app comes in

RefreshYourMac measures the Photos Library and shows its size, and never touches it: it is rated Protected, which means it cannot be deleted in the app, however you ask. The app refuses to touch any .photoslibrarybecause deleting or moving one in Finder can lose photos, and what it tells you instead is what this page says: free space from inside Photos, turn on Optimise Mac Storage, or move the library to another drive by Apple's steps. Its Duplicate Pictures and Duplicate Files categories look in your folders and leave photo libraries closed, for the same reason.

What it does clean is everything around the library that is not your photos: caches, logs, build output, old backups and the rest of System Data. For the order to work in when the disk is nearly full, see Mac storage full.