macOS has many powerful features, but some settings aren’t shown in the standard interface in order to keep things simple and protect system stability. Screenshot formats are one example.
macOS saves screenshots as PNGs by default, which preserves detail but often creates unnecessarily large files. Because the built-in Screenshot app doesn’t offer a native option to change this, you have to look elsewhere.

Fortunately, Terminal provides direct access to macOS’s underlying Unix settings, allowing you to change your default screenshot format with a single command.

Change the Format

1. Open Terminal from Applications > Utilities, or find it with Spotlight.
2. To save screenshots as JPEG, enter:

$ defaults write com.apple.screencapture type jpg

3. Apply the setting by restarting the screenshot service:

$ killall SystemUIServer

Take a new screenshot with Shift–Command–3, Shift–Command–4, or the Screenshot app. It should use the selected format.

Choose Another Format

Replace jpg with a format supported by your macOS version. For example, to choose TIFF:

$ defaults write com.apple.screencapture type tiff

$ killall SystemUIServer

Common format values include:

• png — sharp images and transparency; the usual macOS default.
• jpg — smaller files, useful for photos or sharing.
• tiff — high-quality images that may take up more space.
• pdf — useful when you need a document-style file.

Format support can vary between macOS versions. If a format doesn’t work as expected, use PNG or JPEG, or export the screenshot in Preview.

Change the Format Back to PNG (default)

To restore the usual format, run:

$defaults write com.apple.screencapture type png

$ killall SystemUIServer

Troubleshooting

• The format didn’t change: Run killall SystemUIServer after setting the preference, then take a new screenshot.
• The file still appears to be PNG: Check the filename extension and the current preference. You can also open the image in Preview and use File > Export.
• You want HDR screenshots: On supported Macs with macOS Tahoe 26 or later, open Screenshot with Shift–Command–5, choose Options, then select Capture Format > HDR. HDR screenshots use HEIF; SDR captures use PNG. Apple Support

PNG is macOS’s default screenshot format, but it can create large files. The graphical interface offers only limited format choices; Terminal provides direct access to macOS’s underlying Unix settings. Use the defaults command to choose another format for future screenshots, restart the screenshot service, then capture a new image to check the result.