Change OS X's default screenshot image format
At the prompt, type this:
Replace "image_format" with a file format name, like pdf, png, tiff, etc. Then to take screenshots, Cmd+Shift+4, then drag around the area you want to capture.
defaults write com.apple.screencapture type image_format
Replace "image_format" with a file format name, like pdf, png, tiff, etc. Then to take screenshots, Cmd+Shift+4, then drag around the area you want to capture.
