I am thinking about the way to attach the printed photographs to the wall but not using the frame. And the most interesting idea for me is the use of electrostatics. In addition I have found the following video that shows this process in action: http://youtu.be/r0u85k5EpcE
Also I think that something like this is used in some kinds of wall-climbing robots.
So does somebody know how it works? I suppose that the materials of the objects are very important here. Probably it works because the wall and photo are made of paper, and plastic between them gets charged and consequently attracts paper. What other materials or combinations of materials can provide this effect? And how is the electrostatic charge transferred to the material (plastic foil and paper)? I know only about objects gaining electrostatic charge after rubbing them. But in the stick from this video it must be done by some simple electric circuit...