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Your Photos Library Is Too Big for Your Mac: What Actually Helps
Three things shrink a Photos library on a Mac: turn on iCloud Photos with Optimize Mac Storage, move the library to an external drive, or delete what you do not need and empty Recently Deleted. Compressing the files inside the library package is not one of them. Do not do that.
Why is my Photos library so large?
Photos keeps the original of every photo and video you import or sync, plus edit data and thumbnails. Video and Live Photos are usually the heaviest part, and a library that has been copied or merged over the years often holds duplicates. The library is a single package called Photos Library.photoslibrary, so Finder shows one big item.
To see its real size, select it in Finder (it is in your Pictures folder by default) and press Command-I. To see what is in it, you have to use Photos itself, not the package.
How do I reduce the size of my Photos library on a Mac?
| Option | Frees space on the Mac? | What you give up |
|---|---|---|
| iCloud Photos + Optimize Mac Storage | Yes, automatically when the disk fills | Full-resolution originals live in iCloud; the Mac holds smaller versions and downloads on demand. Needs an iCloud plan big enough to hold everything. |
| Move the library to an external drive | Yes, fully | The drive must be connected to open the library. |
| Delete photos and videos, empty Recently Deleted | Yes, once emptied | The photos are gone. |
| Delete duplicates | Yes | Nothing, if they really are duplicates. |
| Export, compress, re-import | Rarely | Time, edit history, and the originals you must delete by hand. |
| Compress files inside the .photoslibrary package | No: it can corrupt the library | Everything. Do not. |
In Photos, the iCloud choice is under Photos > Settings > iCloud. Turn on iCloud Photos, then select Optimize Mac Storage. Apple documents the behavior in the Photos User Guide linked below. It only helps if the originals are safely in iCloud first, so wait for the upload to finish before you delete anything.
What should I delete first?
- Open Photos and sort or filter for videos. A few long clips outweigh thousands of stills. Delete the ones you will not watch again.
- Open the Duplicates album in the sidebar (macOS Ventura and later) and merge what Photos finds.
- Check Utilities for Screenshots and other clutter, and delete what you do not need.
- Open Recently Deleted and choose Delete All. Items sit there for a limited time first, and the space does not come back until it is emptied.
Do all of this inside Photos, never from Finder inside the package. Photos tracks every file in its own database, and a file removed behind its back can leave the library broken.
Can I keep my Photos library on an external drive?
Yes. Quit Photos, drag Photos Library.photoslibrary to the external drive in Finder, then hold Option while opening Photos and choose the library on the drive. If it should be the one that syncs with iCloud, open Photos > Settings > General and click Use as System Photo Library. Format the drive as APFS or Mac OS Extended, not FAT32 or exFAT, which Photos does not support for a library. Keep a backup: one drive is one point of failure.
Can I compress my Photos library?
Not in place. Photos has no compress command, and shrinking the files inside the package breaks the database that points at them. What you can do is shrink copies. Select photos in Photos, choose File > Export > Export Photos, pick JPEG and a medium quality, then compress the exported folder with a tool. Only after you have checked the copies should you delete the originals from Photos. That trades quality for space, so decide which photos deserve it. Family albums probably do not; screenshots and camera-roll duplicates probably do.
To shrink the exported copies yourself, sips can resize a folder in one pass. See our sips command guide for the options. For the general question of where the bytes go, read why a photo file is so large.
mkdir -p small
sips -Z 2400 -s format jpeg -s formatOptions 80 *.jpg --out small/When is Smol the wrong tool for this?
Smol is the wrong tool for the library itself. It does not read or modify a Photos library, and it should never be pointed at the package. For freeing space, iCloud Optimize, an external drive and deleting are all free and do more. For a few exported photos, Preview or sips is enough.
Smol earns $29 (once, one Mac) when you have exported a big folder and want smaller JPG, WebP or AVIF copies of the whole lot in one drag, with originals left alone and nothing uploaded. It also helps on storage-hungry folders outside Photos, as described in Mac storage cleanup. Compare options in the best image compressor for Mac roundup, or see pricing.
How we checked this
Read Apple’s Photos User Guide for iCloud Photos, Optimize Mac Storage, duplicates and moving a library. No library was opened or modified. Smol limits come from our fact sheet. Facts last checked . We make Smol, so treat our claims about it with the same care as any vendor’s, and see our editorial policy.
Photos library size: common questions
Why is my Photos library bigger than the photos I see?
The library holds originals, edit data, Live Photo video, thumbnails and previews, and it keeps the original even after you edit a photo. Videos and Live Photos add the most. Select the library in Finder and press Command-I for its size, then sort by videos inside Photos to find the heavy items.
Does Optimize Mac Storage delete my photos?
No. It keeps full-resolution originals in iCloud and stores smaller versions on the Mac when disk space runs low, downloading originals when you open them. It does depend on iCloud holding everything, so confirm the upload has finished and that your iCloud plan has room before relying on it.
Is it safe to move my Photos library to an external drive?
Yes, if you quit Photos first, copy the whole library package, then open it by holding Option when launching Photos. Use an APFS or Mac OS Extended drive, and keep a separate backup. The drive must be connected whenever you want to open the library.
Can I delete files inside the Photos library package?
No. Photos tracks every file in a database, so removing or replacing files from inside the package can corrupt the library or leave photos missing. Delete from within the Photos app, then empty Recently Deleted. Treat the package as a single locked item in Finder.
Will compressing exported photos hurt quality?
Slightly, and it cannot be undone once you delete the originals. A JPEG at a sensible quality looks the same at normal sizes but loses detail when printed large or cropped hard. Keep originals of anything you care about, and compress only copies you have compared on screen.
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