It is incredible how many pictures are rotated counter-clockwise. I would estimate their share as 20-25%. There seems to be some substantial property of human hand movement that makes your finger go not straight down, but slightly rightward, and not straight right but slightly upward. This is especially strange when you think about European cursive handwriting where letters are rotated in the opposite direction, clock-wise! Obviously, the movement of a pen and that of a finger are fundamentally different.