“Where did my disk go?” is 80% of the time, one folder: Photos Library.photoslibrary. It absorbs every photo and video you’ve ever shot (and every one you deleted in Photos but macOS kept in the library’s trash).

Here’s how to find its true size, clear the fat safely, and keep your library intact.

Measure it properly

The folder hides its weight. Size it with du:

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

⚠️ Not ls -l — the Finder’s size column often shows the logical size, but APFS clones and copies can make the real footprint differ dramatically. du is your truth-teller.

If that shows 100 GB while “photos I care about” ≈ 20 GB, the library has a hoarding problem.

Where the hidden weight is

Inside /Photos Library.photoslibrary/:

originals/ — every original photo & video (the real weight)
Masters/, Thumbnails/, DirtyThumbnails/, FaceMetadata/
current/index.photolibrary/ — the SQL database
current/timeline/ + the trash: Photos keeps items you “delete” in an internal trash until you empty Photos’ own Recently Deleted

The classic sink: old videos. 4K phone video, screen recordings, and AirDropped video fills libraries while “photos” stay light.

Safe to delete? The honest list

Item	Safe?	How
Photos’ Recently Deleted album	✅	Trash old ones in Photos → Recently Deleted → Delete All (they’re already deleted once)
Duplicate photos	✅	Use content-hash duplicate finders (photo-aware) — bytes reclaimed, keep one copy
Old iMovie/Final Cut event libraries	✅	External to Photos; safe if project archived
The actual originals	❌	That’s your library
System “optimized” cache (iCloud Photos)	⚠️	Only if you re-enable iCloud Optimization (see below)

The reclaim steps (no data loss)

1. Empty Photos’ real trash

In Photos: Recently Deleted → Select All → Delete. These are your previously-deleted items — fully safe. This alone returns a surprising GB on huge libraries.

2. Kill duplicate photos (the pure win)

Duplicates are the most common real reclaim: two copies of every screenshot, an imported set + an edited copy, etc. Since they share bytes or exact content, finding them by content hash (not name or size) is the only honest method.

You can do it manually (filter → group by kind) or with a duplicate finder that hashes file contents. Exact-byte duplicates are safe to remove — keep one copy of each group.

3. Recover old 4K videos you forgot

Filter Photos by Videos, sort by size/date, and archive the mega-files you never re-watch (export to an external disk, then delete the originals). Screen recordings are prime targets.

4. If you use iCloud Photos: enable “Optimize Mac Storage”

Photos → Settings → iCloud → Optimize Mac Storage. macOS keeps lightweight thumbnails locally and pulls originals on demand. This can cut the photoslibrary from 100 GB to ~10 GB. Tradeoff: viewing a photo requires the network.

This does not delete anything from iCloud — it frees the local copy.

When NOT to prune blindly

Never delete originals/ — that’s your library database + masters.
Don’t “clear storage” via Finder by deleting inside the bundle — Photos caches are managed.
Don’t sync-trim via iCloud unless you accept network-dependent originals.

If the number still looks wrong after the steps above, use disk map tooling to see what else is on the same volume — the mystery is often a Docker.raw (guide), node_modules (guide) or Time Machine snapshots (guide), not Photos.

The visual way

A disk analyzer shows the photoslibrary as one giant block, then lets you drill inside to see originals vs thumbnails vs the database before you touch anything. Everything is staged to the Trash for review — reversible, no blind deletion, all local.

DiskInsight renders your whole disk by byte cost (including the photo library and every hidden folder), ranks duplicates by content hash, and never deletes anything behind your back. 100% local, zero telemetry, one-time price.

TL;DR

du -sh ~/Pictures/Photos Library.photoslibrary — know the real size.
Empty Photos’ Recently Deleted.
Delete content-identical duplicates (hash-based, keep one).
Archive old 4K videos.
Consider Optimize Mac Storage if iCloud backup is on.

Your photo library stays; the bloat goes.

Get DiskInsight Pro · $9.99 one-time to find the Photos Library and every other stealth folder. Or start with the Mac storage cleanup guide.

Your Photos Library Is 100GB+ — Here's How to Shrink It