Who is the target of the prohibition of graphical representations of Allah and Muhamad?

Who is the prohibition addressed to? Believers, or everyone? In other words, is it a requirement of faith where Muslims are themselves banned from the action, or whether they should also actively seek the picture not to be published by non-Muslims? I am interested in two cases: - generic representation (for instance the one that got López Prater fired recently, a 14th-century image that shows a winged and crowned Angel Gabriel pointing at the Prophet Muhammad and delivering to him the first Quranic revelation) - caricature Finally, I assume a country where blasphemy is not a felony (and the legal system is not base on Shariah)