Originally posted by Tarmac
Those don't even look like the same bulldozer. Look at the placement of lights on the roof.
Not to mention the background is quite different between the two photos. It's pretty obvious to me that those pictures weren't taken right after each other, as popularly represented.
same dozer, the lights are mounted on the lifts and go up and down with the blade, they are not on the roof (cab) of the dozer.
The time of day, location, forground, and background are however all differant and were not even close to taken at the same time.
edit to post... I think you may be right, look at the guard mounted on top of the blade the vert. parts seem closer together on one blade then the other. the lights are articulated to the blade lifts and go up and down.