I believe that the graphic designer has intentionally put the Zack's face onto the bridge's block, making it more debatable for us to agrue whether it's our brains are fooling us or not. The designer didn't change the colour of Zack's body, just the opacity that he changed.

It's the colours what mostly count, look at the enchanted image I've posted. The colour of each block of the bridge are slightly different, plus the colour comparison of his right shoulders and the bridge's background.