Hannes, certainly the pic is photo shopped but you are right they don't cheat.
Sadly, Heinz, it's quite likely that the photo isn't 'shopped. There's a curious subculture amongst owners of big diesel pickups in the US, who enjoy "rollin' coal" and will spend seemingly enormous amounts of money upgrading injectors, inlet & exhaust systems, and programmable ECUs so that they can turn it on and off on a whim.
Wikipedia has a short explanation and a google search will turn up images and videos galore...
