That wall texture thing is a dead giveaway. I've seen so many fakes where the pattern on the wallpaper or bricks repeats in a way real walls never do. You have to zoom way in and look for those cloned patches. Just a quick glance at the background isn't enough anymore.
Forget the walls, check the light. Fake shadows never get the soft edges right or match the light source. It's like the sun forgot how to work in half the picture.