Thieves in the Photo Studio

You have been given the assignment to steal a famous photograph and you break into the photographer's studio at night. The artist has hidden the photo well- it hangs next to two similar copies in the photographer's private gallery. But which photo is the right one? In one corner, a lone computer hums to itself. What's up with the strange arrows? And what do these model photos and this even stranger disk mean? The photographer will be at a vernissage for another hour before he comes back. So you must be quick and solve the photo's puzzle. However, it is known that the forgetful photographer makes notes and gives hints to all important things- and all hints are hidden in his photo studio. And hurry up, time is running out…