If you experience an Mac OS X program to freeze and you cannot exit it by clicking quit or using a keyboard shortcut, you can always force it to quit using the Activity Monitor.
Adding a lens flare can make or break a certain image. The best kind of lens flare is the natural one taken through the actual lens of a camera, but if we do it the right way, we can recreate it using Photoshop just as good.
Lots of people think using a layer mask is only for the advanced Gimp users, fortunately this isn't the case at all. Let me explain you the basic usage of layer mask on a easy to follow step-by-step example.