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Reduce File Size on Mac: 3 Practical Routes

Reduce file size on Mac for video, photos, PDF, and GIF with GetCompress, Preview or QuickTime, and FFmpeg. Free space without deleting project masters.

By Petr Samokhin

Storage warnings often point at Movies, Downloads, or project folders full of media. Much of it is work you still need: screen recordings, photo exports, slide PDF files, and large GIF loops. Shrinking copies frees space while masters stay archived.

See what is using space

System Settings → General → Storage shows which categories dominate. In Finder, open the heavy folders and sort by size.

FolderWhat piles up
DownloadsInstallers, zip exports, one-off PDF decks
MoviesScreen recordings and camera imports
DesktopScreenshot PNG files and quick exports
Project drivesFiles you send to clients, bug videos, photo batches

Delete installers you can re-download. Compress what you need to keep. Empty Trash after you confirm nothing still references those files.

Method 1: GetCompress for mixed folders

Best for: One local pass when a folder mixes video, images, PDF, and GIF.

GetCompress showing file sizes before and after compression for queued media
  1. Open GetCompress and drop the heavy folder into the queue.
  2. Review detected types and pick presets per media (for example 720p email video, image max width, PDF compression).
  3. Preview anything client-facing, then export smaller copies beside the originals.
  4. Archive masters and keep the lightweight copies for day-to-day use.

Processing stays on your Mac. Save presets so the next cleanup is a few clicks. For video megabyte caps, see compress video to a target size on Mac .

Method 2: Preview, QuickTime, and Photos

Best for: One or two files with built-in apps.

Video (QuickTime): open the clip → Edit → Trim → File → Export As → 720p or 1080p.

Photos: Preview → Tools → Adjust Size, then export JPEG. Or Photos → File → Export for camera rolls.

PDF: Preview → File → Export → Reduce File Size, or re-export slides from Keynote at lower quality.

Prefer a short MP4 over a huge GIF when the destination allows video.

Limitation: You open a different app per file type. No shared preset across a mixed Downloads folder.

Method 3: FFmpeg and Terminal

Best for: Scripts and CRF-style video control.

brew install ffmpeg
ffmpeg -i clip.mov -c:v libx264 -crf 23 -c:a aac -b:a 128k clip-small.mp4

For images, sips can resize a folder:

mkdir out
for f in *.jpg; do sips -Z 1920 -s formatOptions 85 "$f" --out "out/$f"; done

Limitation: You maintain commands. See how to compress video on Mac and how to compress images on Mac for deeper settings.

Which method should you use

SituationStart here
Mixed project or Downloads folderGetCompress
One QuickTime clip or one PDFQuickTime or Preview
Scripts and exact encoder flagsFFmpeg
Cleanup stepSafe when
Empty Trash and remove duplicate installersAlways, if you can re-download
Compress screen recordings you still referenceAfter you keep a master elsewhere
Convert huge GIF loops to short MP4Destination accepts video

When a built-in export is enough

QuickTime or Preview can finish one file that already lands under the limit after trim or resize.

GetCompress also works well for that job. It also covers Storage points at a mixed folder and you want one local pass with reusable presets. It does not replace Time Machine, an archive drive, or deleting files you no longer need. For PDF-only work, see how to compress PDF on Mac .

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