when placing a 4x2 picture on a 4x2 wall the picture overshoots the block (top picture) you can see it over shoots onto an air block A + B.

IF I destroy block 7 / 8 as there is no part of the picture on it, the picture frame falls off (bottom picture) not tried the really large pictures yet.

even if I place blocked behind the air blocks A + B (so the picture is on the newly placed blocks (to hold it in place) it still falls off