Vector graphics of the iPad retina, and iPhone retina, both 3.5 and 4" versions. Each image contains two objects, a frame illustrating the device, and a screen rectangle that is exactly the pixel size of the device. So you can design at 1:1 scale, overlay the frame and it appears as a screen shot. Each device has portrait and landscape versions with different shading, to look consistent together. Non-retina versions are supported by scaling the images to 50%.