follow these steps and see the attached picture:
1. open Camera Roll and select picture, select "Use as Wallpaper".
2. use the two finger "gestures pinch" to shrink picture to fit your screen, this turns "Perspective Zoom: Off".
3. hit the "Set" button and "Set Lock Screen".
the shelf picture will now fit correctly...![]()
Is this not because their phone is on zoom setting already?