By default, macOS saves screenshots in the PNG format on your desktop. However, you can change this default file format to JPEG, GIF, TIFF, or PDF using simple Terminal commands.
macOS allows you to change the default screenshot file format to the following:
To change the default screenshot file format, follow these steps:
Example command to change to JPEG:
defaults write com.apple.screencapture type jpg;killall SystemUIServer
The killall SystemUIServer
part refreshes the system to apply the changes.
To revert back to PNG, use the following command:
defaults write com.apple.screencapture type png;killall SystemUIServer