By default, whenever you take a screenshot on a Mac (using the Command + Shift + 3 or Command + Shift + 4 shortcuts), macOS saves the resulting image to your desktop as a PNG file. While PNG files offer excellent, lossless quality with support for transparency, they generate massive file sizes. If you frequently share screenshots via email or upload them to web forums, these large files can cause frustrating delays and exceed attachment limits.
You can force macOS to save all future screenshots in the compressed, universally compatible JPG (JPEG) format by executing a simple command in the Terminal.
How to Change the Screenshot Format to JPG
Because Apple does not provide a simple toggle for this in the standard System Settings GUI, you must use the defaults write command to modify the hidden preference file.
- Open the Terminal application. You can find it by pressing
Command + Spaceto open Spotlight, typing “Terminal,” and hitting Enter. - Copy and paste the following command exactly as written into the Terminal window:
defaults write com.apple.screencapture type jpg
- Press Enter. The command will execute silently without outputting a success message.
From this moment forward, every new screenshot you capture will automatically be saved as a highly compressed .jpg file, drastically reducing its storage footprint.
How to Revert Back to PNG (or other formats)
If you are a graphic designer or need the absolute highest quality image without compression artifacts, you might eventually want to switch back to the native PNG format.
To revert the change, open the Terminal and run this command:
defaults write com.apple.screencapture type png
macOS also natively supports several other image formats for screenshots. If you prefer, you can replace the word “jpg” in the original command with gif, tiff, or pdf depending on your specific workflow needs.