What's wrong with the photography building?

Once you have broken something, it cannot be un-broken.

I suggest starting another game, in another game slot, and being careful with what you thin and destroy. And, if Gremlin Gus, who is with you all the time, warns you that thinning something can ruin something, do not go to the other side of the object, and thin the second one.

Things in Mean Street South are connected to Mean Street North.
I believe that it was the thinning of the two sides of the robot water thing in the middle of Mean Street South (and Oswald automatically zapping the power boxes inside) that caused the Oswald water tower in Mean Street North to topple, and block the camera shop.