How to Compress PNG Files on Mac (Free Methods)

By admin · Jun 18, 2026

Mac users have several built-in tools for working with images, but not all of them offer true PNG compression. In this guide, we'll show you 5 ways to compress PNG files on macOS — from the simplest to the most powerful.

Method 1: Use compresspngfile.com (Best Results)

The easiest and most effective method — works on any Mac with any browser.

1. Open Safari, Chrome, or Firefox on your Mac
2. Go to compresspngfile.com
3. Drag your PNG file from Finder onto the upload zone
4. Compression completes in 2–5 seconds
5. Click Download to save the optimized PNG

Achieves up to 80% file size reduction. Works on macOS Ventura, Sonoma, Sequoia, and all older versions.

Method 2: Use Preview App (Built-in — Basic)

macOS Preview app can reduce PNG size by changing the image dimensions. It cannot perform deep PNG data compression.

1. Double-click your PNG to open it in Preview
2. Go to Tools > Adjust Size
3. Reduce the width/height values (make sure "Scale proportionally" is checked)
4. Click OK, then File > Export
5. Choose PNG format

Best for: Making an image physically smaller (fewer pixels). Not for compressing the actual PNG data.

Method 3: Use Automator for Batch Compression

macOS Automator can resize multiple PNG images in batch:

1. Open Automator (Applications > Automator)
2. Create a new "Workflow" or "Quick Action"
3. Add action: Files & Folders > Get Specified Finder Items
4. Add action: Photos > Scale Images (set your target size)
5. Run the workflow on your PNG files

Note: Automator performs dimension scaling, not PNG data compression.

Method 4: Use the sips Command in Terminal

macOS has a built-in command-line tool called sips (Scriptable Image Processing System):

1. Open Terminal (Applications > Utilities > Terminal)
2. Navigate to your image folder: cd ~/Desktop
3. Run: sips -Z 800 yourimage.png

For batch processing all PNGs in a folder: for f in *.png; do sips -Z 1200 "$f"; done

Limitation: sips resizes but does not perform pngquant-level compression.

Method 5: Use ImageOptim (Free Mac App)

ImageOptim is a free macOS app that performs lossless PNG compression:

1. Download ImageOptim from imageoptim.com
2. Open the app and drag your PNG files into the window
3. ImageOptim automatically compresses and overwrites the original files

Typical savings: 10–30% (lossless). For 70–80% savings, use compresspngfile.com instead.

Comparison of Mac Methods

Conclusion

The best way to compress PNG files on Mac is compresspngfile.com for maximum compression (up to 80%) with zero installation. For Mac-native workflows, combine sips for batch resizing with compresspngfile.com for final compression.