Some time you need to capture screenshot in Mac and want to save in specific file format. On Mac OS X the default file format for screen shot is PNG but if you want that your Mac must save screen shots in any other file format for example as JPG, GIF or PDF then just apply the following method to do so.

See also
How to Take ScreenShot On Mac Using Terminal
How to Set a Folder to Save Screen Shots on Mac
How To Set Timer To Take Screenshot On Mac Using Terminal

How to change default Mac screenshot file format

Step 1

Click on Finder

Navigate to Applications > Utilities and launch Terminal

Step 2

Type the following command in Terminal and hit Enter key

defaults write com.apple.screencapture type JPG

you can specify different file formats like GIF, PDF, etc as we specify JPG above in screen shot.

Step 3

Now, restart your system and take a screen shot and check its extension, that’s set to JPG. In this way you can revert the screen shot file format just by typing a command in Terminal