ARPhotoView

Use your iPhone's camera to view pictures in augmented reality.
Either select a saved photo or take a new one. Once an image is selected, you can place the image in 3d space and interact with it as if the image was in the real world.
This app gives you the ability to modify the image's dimensions, rotation, orientation, and position for ultimate customization.
Tap the info button in the app for helpful tips.
Currently you can only place one image at a time. A future update will allow multiple.