Nocturne Easter Egg - Picture of the Developers of Nocturne

Start act 4 of Nocturne.
At the hallway you get out of the lift after having talked to the secretary, who opened the door to get to it.
Just before the next (and only) door where you get to the hall with the offices inside, take a closer look at the picture (by that I mean clicking on it with the action button), located to the right of the door.
It shows the developers in an "ancient" mood.