You can take a snapshot of any screen on your iPad by pressing the Home button
and the Sleep/Wake button at the same time.
You’ll see a white flash on the screen, confirming the picture was taken. The screenshot is saved in your Photos library in the Camera Roll. These images can be easily transferred to your computer for further processing. That’s how I made the iPad screenshots for my book and for many of the posts here on the website.
Screenshots are handy for teaching and training. For example, I lead workshops and seminars on using the iPad. Screenshots can be captured, then annotated and displayed as part of a presentation. Screenshots are also handy for capturing that high score screen from your favorite game.
You can use the screenshot technique to take pictures of zoomed photos too. In the Photos app, you can use two fingers to zoom in to a face in a photo (reverse pinch), and then take a screenshot while zoomed in.
Don’t hold the Home and Sleep/Wake buttons too long or you’ll reset the iPad.
Excerpt from my eBook iPad Academy: Tips, Tricks and Clever Techniques