Like the iPhone, you can use a custom wallpaper. First, use Safari to find the image you want.
(Try Interfacelift.com, which has iPad-sized images.) View the image, then press and hold on the screen and select Save Image.
Now, go to Settings, Brightness & Wallpaper. Flick to the right, go to Saved Photos, and select the image.
Press the Set Lock Screen or Set Home Screen option, or Both.
"iPad Tips and Tricks : Use a custom wallpaper "
Reference : top-ipad-video-converter.com