Slo-mo is the most wasteful format per watched second: ~300MB/min, and 90% of every clip is throat-clearing before the action. Time-lapses are the opposite problem — tiny files, hundreds unwatched. Both clean fast.
The quick answer
Open Photos > Albums > Media Types > Slo-mo, trim each keeper to the action (save as new clip, delete the original), delete the rest. Then do the same in Time-lapse keeping one winner per subject. Empty Recently Deleted to realize it.
Step 1: Trim, don’t just delete
- Open a slo-mo clip, tap Edit, drag the handles around the action.
- Tap Save as New Clip — the 15 seconds that matter, ~75MB saved per trim.
- Delete the original.
What this gives you: the moment at a tenth of the weight. What this does not give you: decisions on the 40 near-identical skateboard attempts. Keep the best landing, delete 39 — same muscle as burst cleanup.
Step 2: Time-lapse triage
Sort by date, keep one winner per subject (one sunset, one drive, one build). Files are small; the win is findability, not gigabytes — and fewer files to back up (backup guide).
Step 3: Shoot smaller
Slo-mo defaults to 1080p240 — fine, the fix is trimming, not settings. For test clips, shoot regular video first and reserve slo-mo for the real attempt. General video math in our video size calculator.
The bottom line
Trim the action, crown one time-lapse per subject, empty the trash. The most fun formats, minus 90% of their weight.