Automatic Folder Compression on Mac

The export finishes at 6 PM. By Monday the shared drive holds forty new PNG UI shots, six MOV bug clips, and three scan PDFs nobody resized. You could drag each batch into a compressor every morning, or you could point a watch folder at ~/Exports/web and let the same preset run while you make coffee.

Automatic folder compression on Mac makes sense when files land in the same directory on a predictable schedule and the output spec does not change job to job.

Method 1: GetCompress folder monitoring

Best for: “New file appeared” jobs with a stable preset (web JPEG, Slack MP4, email PDF).

1. Open GetCompress and save a preset for the destination (for example “Web JPEG 1920” or “Slack MP4 720p”).
2. Turn on folder monitoring in settings.
3. Pick a watch folder and attach that preset.
4. Choose an output folder that is not the same as the watch path.
5. Drop three test files, check size and quality, then point production exports at the watch folder.

Processing stays on your Mac. Use target file size on video when portals cap megabytes. Exact target size is video only.

When folder monitoring beats manual batch

Signal	Example
Same folder every week	Render output directory
Trigger is “file appeared”	AirDrop ingest, screen capture folder
Settings stable for a month	Web JPEG 1920 px, Slack MP4 720p
Team shared Mac	One preset name everyone recognizes

If the pain is a one-time email bounce, read the email attachment size limits guide first. You may only need a single batch run, not permanent monitoring.

Stop monitoring when every job needs different codecs. Automation fails when “smaller” is vague and the preset drifts. Write down max width, quality, codec, and output path before you enable the watch folder.

Common watch folder setups

Watch folder	Preset	Result
~/Exports/web	Web JPEG 1920 px	Ready for CMS upload
~/Movies/Captures	MP4 1080p	Smaller bug repro clips
~/Documents/Scans/in	PDF medium	Lighter attachments
~/Downloads/heic-ingest	HEIC to JPEG 3000 px	Listing-ready stills

Output goes to a sibling folder you pick (~/Exports/web/out, for example). Originals stay in the watch folder unless your workflow moves them after success.

For one-time folder batches without ongoing watches, see the batch compress and convert guide for Mac .

Presets that survive automation

Preset field	Write it down
Max width / height	1920 px long edge for web
Video resolution	1080p vs 720p for ticket clips
Target file size (video)	15 MB cap when email is the destination
Output format	JPEG, MP4, compressed PDF
Output directory	Avoid overwriting sources

Name presets for the destination, not the mood: “Slack MP4 720p 15MB”, not “small video”. Start with one watch folder and one preset. Add a second path only when the first is stable for a month.

Method 2: Hazel, Automator, or FFmpeg

Mac teams already automate with Automator folder actions, Shortcuts, or Hazel rules that call shell scripts.

Tool	Strength	Maintenance
Automator folder action	Built-in, no extra purchase	Breaks occasionally after macOS upgrades
Hazel	Rich conditions (size, weekday)	You maintain the script Hazel calls
Terminal + FFmpeg	Full control	Someone owns codec flags
GetCompress monitoring	Preset UI, preview, mixed media	Enable in app settings

Hazel shines when you need conditions beyond “new file appeared” (only PNG over 5 MB, only on weekdays). GetCompress covers the simpler “compress everything new with preset X” case without extra software.

Keep a manual fallback (drag-and-drop into GetCompress) for deadline weeks when a folder action stops firing after an OS update.

Avoiding duplicate and failed runs

Problem	Fix
Same file processed twice	Move outputs elsewhere; do not watch the output folder
Partial writes	Wait until the export app finishes before files appear in the watch folder
Locked files	Screen recorder still writing; exclude temp extensions if needed
Wrong preset on mixed folder	Split ingest folders by media type

Test on a copy folder first. Drop three representative files (PNG, MP4, PDF) and confirm output size and quality before you point production exports at the watch path.

When a one-time batch is enough

Drag a folder into GetCompress, use Preview, or run a short sips / FFmpeg loop when the job is a one-off email bounce or a single shoot.

GetCompress folder monitoring also helps when the same export path fills every week and the preset is documented. Processing stays local. It does not replace Hazel for complex file rules, and it does not replace a full video editor. For the Windows watch-folder setup, see automatic folder compression on Windows .