How to convert screenshots to JPEG automatically on Mac

What this does

macOS saves screenshots as PNG, which keeps every pixel crisp but produces a much larger file than most screenshots actually need. This rule converts each new screenshot to a smaller JPEG the moment it lands, and keeps the original PNG alongside it, so you lose nothing.

What you’ll build

A rule that matches files whose name begins with “Screenshot” and whose extension is png, then converts each to JPEG while keeping the original.

Open the rule editor

This walkthrough happens inside FilesAutomator itself, so install it from the Mac App Store first if you have not already, then open it. In its toolbar, choose Add, then New Automation Rule.

Name the rule and choose a folder

Name it something like “Convert my screenshots to JPEG” and use Add Folder to choose the folder your screenshots land in.

Build the condition

Leave the group set to “All of the following are true”.

Add a condition: Name begins with Screenshot.

Add a second condition: Extension is png.

This checks the extension rather than Kind, deliberately. Once a screenshot has been converted its extension becomes jpg, so this condition naturally stops matching it on the next scan. A Kind based condition would keep matching the new JPEG too, and try to convert it again every time.

FilesAutomator

Add the action steps

Step 1: Convert image

Choose Add Step, then Convert image. Set “Convert to” to JPEG, and leave Quality at its default.

Set “Keep the original file as” to Left untouched, new file created separately, so the original PNG stays put and the smaller JPEG appears next to it.

FilesAutomator

Turn it on

Select Create Automation Rule, then switch the rule on. Every screenshot you take from now on gets a smaller JPEG copy automatically.

A faster way

The template gallery inside FilesAutomator already has this rule ready to install, named Convert screenshots to JPEG.