Rabid Vegan
Motion/position sensors like a Wiimote, only much more acurate, and a series of side-by-side airbrushes that activate when the computer tells them they're in front of a spot that needs painting, would be my guess. Would also explaint the noise. Sweet piece of tech!

Tyrathca
Consider my mind un-broked. Much obliged good sir!

rulestein
It is a large silk screen. When the paint dries, they will peel away that paper and the image will be on the wall.

Repomancer
You are a large idiot, rulestein.