Photos library (Mac)
Also known as: Photos Library.photoslibrary, Mac photo library size, where Mac photos are stored
The Photos library on a Mac is a single package file (Photos Library.photoslibrary) in your Pictures folder that holds all your images, videos, edits, and thumbnails. It is often the largest single item on a Mac.
- A package file in the Pictures folder
- Often the single largest item on a Mac
- Optimize Mac Storage keeps smaller local copies
Where it lives and what it contains
By default the library is at Finder > Pictures > Photos Library.photoslibrary. It looks like one file but is actually a package: right-click and choose Show Package Contents to see originals, edited versions, and thumbnails inside. Keeping edits and originals together is what makes it grow.
If iCloud Photos is on, this library mirrors your iCloud photos. Whether full-resolution copies live on the Mac depends on your download setting.
Optimize Mac Storage
In Photos > Settings > iCloud, choosing Optimize Mac Storage keeps full-resolution originals in iCloud and stores smaller versions locally, downloading originals only when needed. Download Originals to this Mac keeps full-size copies on disk, which uses much more space. Deleting from the Photos app moves items to its own Recently Deleted album, where they linger about 30 days before space is freed.