Here is a excellent Apple iPad Application which is completely free of cost and which can convert your Apple iPad into a Digital Photo Frame with HD Quality display. Even though the iPad features inbuilt Apps for displaying the uploaded photos using the Slideshow option, this application can be a added boost because its sole job is of displaying all your photos in different layouts and formats as shown in the below screenshots.
App Name : Digital Photo Frame HD by Smudge Apps
Great digital frame 🙂