http://eu.battle.net/d3/en/blog/10538390/diablo-iii-at-gamescom-2013-08-08-2013#best
Specifically
Anyone else remember these early gameplay videos, watching them over and over... imagining how awesome d3 was going to be and how you would probably be playing it for eternity.
Ahh such innocence.
I guess it isn't fair to look too deeply into this, marketing probably have no idea how old the media they work with is. I still think its odd given how hard it is to take a current screenshot.