Apple made taking a screenshot (screen capture) of your iPad screen super easy: Press the home button and power button at the same time. Your screen will flash white and you'll hear a camera shutter sound effect. An image of your screen as it appeared will be saved to your Photos.app Camera Roll in the PNG file format.
As of Photosmith 3 for iPad, we do not import or sync PNG files. Thus, iPad screenshots will NOT appear in Photosmith 3.