Changing screenshot file formats Mac OS X

Using terminal it is easy to change the file format that screen shots are captured by the Mac OS X system.  Simply open up terminal and enter the following command.

defaults write com.apple.screencapture type "extension"

Replace the "extension" word in the command above with the name of the file extension that you actually want as a screenshot. 

For JPG you could type the following command:

defaults write com.apple.screencapture type JPG

You can use PDF, GIF, PNG, and others

Though I used Yosemite 10.10 this should work no problem in Snow Leopard 10.6, Lion 10.7, Mountain Lion 10.8, Mavericks 10.9, or El Capitan 10.11