I’m currently working on a React Native project and I take a lot of screenshots from the iOS Simulator. Each one comes out at 1206×2622 pixels, way too big to attach to GitHub PRs without cluttering the conversation. I found myself opening Preview, resizing, saving, and repeating this dance dozens of times a week. There had to be a better way.
While my immediate need was simulator screenshots, this applies to any situation where you regularly deal with oversized images: blog posts, documentation, bug reports, etc.
Automator to the Rescue
macOS ships with Automator, a tool for creating automated workflows. One of its most useful features is Quick Actions, workflows that appear directly in Finder’s right-click menu. Perfect for this kind of repetitive task.
The Workflows
I created two workflows, one for 25% and one for 50%, because different situations call for different sizes. Both follow the same structure:
- Duplicate the selected files (so the originals are never touched)
- Scale the copies (using the built-in Scale Images action)
That’s it. Select some images in Finder, right-click, pick “Resize by 25%” or “Resize by 50%”, and you get smaller copies sitting right next to the originals. No apps to open, no dialogs to click through.
Creating It Yourself
- Open Automator and create a new Quick Action
- Set “Workflow receives current” to image files in Finder
- Add the Duplicate Finder Items action (this protects your originals)
- Add the Scale Images action, select “By Percentage”, and set it to 25 (or 50)
- Save it as “Resize by 25%” (or “Resize by 50%”)
Once saved, it shows up in Finder > right-click > Quick Actions whenever you select image files.
Why Two Sizes?
For my iOS Simulator screenshots (1206×2622), here’s how the two options compare:
| Percentage | Result for 1206×2622 | Good for |
|---|---|---|
| 50% | 603×1311 | GitHub PRs, documentation, sharing |
| 25% | 301×655 | Thumbnails, quick previews |
In practice, I reach for 50% most of the time, it’s detailed enough for PR screenshots while being small enough that GitHub doesn’t complain. 25% is handy when I need something even more compact.
The Dotfiles Connection
As with most of my macOS customisations, this workflow lives in my dotfiles repository. Automator workflows are just bundles (directories with a .workflow extension), so they’re easy to version control. To install on a new machine, you just copy the .workflow file to ~/Library/Services/ and it’s immediately available in Finder.
cp -r "Resize by 25%.workflow" ~/Library/Services/
cp -r "Resize by 50%.workflow" ~/Library/Services/
If you’re curious about the rest of my setup, I wrote about the broader dotfiles philosophy.