OS X has a built-in screen capture function, but it is pretty limited. For example, Command-Shift-4 lets you define a rectangle to capture. Command-Shift-4 followed by the spacebar will capture a window. You can also capture your entire desktop with Command-Shift-3, and other commands will save the result to your clipboard.
Sometimes, those basic features are not enough. Apple bundles a utility called Grab with OS X that adds more features, but it still falls short for many users. Enter Screensho
