Your Mac has the ability to take screenshots with just a keyboard shortcut or two. If you want a few more advanced capabilities, you can use the included Grab application to take screenshots.
But neither of these screenshot options provides an easy way for you to specify your preferred graphics file format for screenshots. Luckily, you can use Terminal, an application included with OS X, to change the default graphics format.
Terminal to the Rescue
As is the case with many of OS X's defaults, you can use Terminal to change the default file format for screenshots.
- Launch Terminal, located at /Applications/Utilities.
- Type or copy/paste the following commands into the Terminal window. Press the return or enter key after you enter each line of text:
defaults write com.apple.screencapture type jpg
The above commands will set the file format to JPG. You can use any of the following for the value following "Type" in the first command above: jpg, tiff, gif, png, or pdf
By setting the default screenshot graphics format to one of the file formats you use the most, you can streamline your workflow.