The problem with any form of censorship is who gets to decide what to censor. In many countries the Sports Illustrated swimsuit issue would be pornographic. Some societies might find any pictures of women in shorts or even pants offensive.
I am concerned with violent content, but what if all pictures from war zones were banned since they often depict horrifying brutality. A society confronted by the gruesome aspects of war might not be so inclined to support warlike activities, while not having access to these pictures might make war in some ways "clean". Those who oppose abortion would likewise not be happy if they were unable to avail themselves of the graphic photos used to great affect to raise awareness.
I have no problem with reasonable restrictions -- age restrictions on certain types of material for example. But so many countries use censorship to perpetuate their regimes, instead of working to make their societies free. I dislike the idea of anyone having the ability to censor content for any reason.