To create these they, got some vinyl prints from a large format printer and attached them to 1″x2″s that had been painted black. (You could also use Coroplast for this.) The lumber gave them some rigidity so they could be self-supporting. Then they fixed the frames to the walls.
The frames were 4×8′ with some cuts to give them unique angles.
They chose to use vinyl because they planned to change out the images every 3 or 4 months.
They used RGBW LED lights on them, which were accented by the colors used in the prints.