60 GB of memories you forgot were local: taming your Photos Library
You check your Mac's storage breakdown and Photos claims 60, 80, maybe 120 GB. That number feels impossibly large — especially if you're paying for iCloud Photos. Aren't those supposed to be in the cloud?
They are. But macOS also keeps copies locally, and the rules for which copies stay on disk are easy to misunderstand. Let's sort this out without deleting a single photo you'll regret losing.
Where your Photos Library actually lives
By default, the library sits at ~/Pictures/Photos Library.photoslibrary. It's a single package file that contains every photo and video the Photos app manages — originals, edited versions, thumbnails, and a database.
You can right-click it in Finder and choose Show Package Contents to peek inside — but don't move or delete anything in there manually. The internal structure is not meant for human editing, and one wrong move can corrupt the database.
Why iCloud Photos doesn't always save local space
When you enable iCloud Photos, your Mac uploads everything to the cloud. But by default it also keeps full-resolution originals on your startup disk. That's why the library stays huge.
The magic switch is Optimize Mac Storage, found in Photos → Settings → iCloud. When turned on, macOS replaces full-resolution files with lightweight thumbnails once your disk starts filling up. Originals stay in iCloud and download on demand.
How to check what's local vs. cloud-only
Open Photos, go to Library → All Photos, and scroll to the very bottom. You'll see a summary line: how many photos and videos are in the library, and whether originals are stored on this Mac or in iCloud.
If it says "Originals are on this Mac," your library is fully local. If it mentions downloading originals, some files are cloud-only thumbnails.
Reclaiming space — the safe path
- Turn on Optimize Mac Storage. This is the single biggest win. Go to Photos → Settings → iCloud → Optimize Mac Storage. Give it a few hours — macOS offloads originals gradually.
- Delete what you genuinely don't want. Use Albums → Recently Deleted to see what's pending permanent removal. Photos stay there for 30 days before being erased from iCloud too.
- Review large videos. Sort your library by file type and look for videos — a single 4K clip can be 3–5 GB. If you don't need it on this Mac, Optimize Mac Storage will eventually offload it, but deleting unwanted videos speeds things up.
What about multiple Photos Libraries?
Some people end up with more than one library — an old iPhoto Library, a secondary Photos Library from a migration. Each one sits in ~/Pictures and takes its own space. Open Photos while holding Option to see all available libraries.
If an old library is just a duplicate of what's already in your main library, you can archive it to an external drive and delete the local copy. But verify first — open it and spot-check that everything important is already in your primary library.
What NOT to do
- Don't delete
Photos Library.photoslibrarydirectly. If it's your System Photo Library, deleting it may orphan your iCloud Photos sync. - Don't manually remove files inside the package. The Photos database will lose track of them and may corrupt.
- Don't rely on iCloud as your only backup. iCloud syncs deletions too — if you delete a photo and empty Recently Deleted, it's gone from every device.
If your disk space problems go beyond Photos — caches, system data, old app leftovers — our guide to System Data covers the rest of what's quietly eating your storage.
Photos are yours. Caches are clutter.
Gigatidy never touches your photos, documents, or personal files. It finds and cleans only the junk — caches, logs, broken leftovers — so your library has room to breathe.
Meet Gigatidy →FAQ
Will Optimize Mac Storage delete my photos?
No. It replaces full-resolution local copies with smaller thumbnails. Your originals stay safely in iCloud and download automatically when you open them.
Can I move my Photos Library to an external drive?
Yes — quit Photos, drag the library file to the external drive, then open it from there while holding Option. But iCloud Photos sync only works with a library on a permanently connected drive, so this is best for archive libraries.
How long does Optimize Mac Storage take to free space?
It depends on library size, but macOS offloads files gradually over hours or days. It prioritizes older, less-viewed media first. You won't see instant results, but the space savings grow over time.