Here are two new trackpad gestures that will make using Photo Booth a lot easier when you are using it in full screen mode.
If you focus the mouse over the special effects in Photo Booth Mac OS X Lion will now let you use a two-fingered swipe to the left or to the right on your trackpad to navigate through all the different special effects. Once you find the one you like click to select it.
If you already collected photos and movies in Photo Booth you’ll see them stored in a camera roll at the bottom of the Photo Booth screen. You can use the same gestures mentioned above to scroll through them while your mouse is focused on the camera roll.