There’s a widespread idea that image manipulation is difficult and only done with lots of expertise using expensive tools. Let’s put that idea to rest. Check out the video below for an idea of how easy it is using the Preview app. You might not get “professional” results but you can accomplish a lot with such tools, and have a little fun while you’re at it
http://www.youtube.com/watch?v=i9sPRQtNYTM