It's pretty obvious from the seams on the outer frame of the mirror that this isn't a blockland-only fake. So there's two possibilities:
1. It's real
2. It's faked as a photomanipulation, in which case you wouldn't see any construction differences, because there are none to find.
edit: btw try this: stand in your bathroom and try to see out the door through the mirror. Now turn to face the door. WHAT YOU CAN SEE CHANGED. magic?!