Change the default macOS screenshot format

By default macOS saves the screenshots you take in PNG format. You can change the file format to JPG, GIF, TIFF or PDF.

To change the default screenshot file format, launch the Terminal app. To change the format to JPG, enter the following two commands in the terminal:

$ defaults write type jpg
$ killall SystemUIServer

The killall command basically reloads the macOS SystemUIServer software to effect the changes.

To change to PDF format:

$ defaults write type pdf
$ killall SystemUIServer

Similarly, to change to other formats, just replace the format string in the command above.