That's a good point, Don, and it raises an interesting problem in theology; while Christianity in the main stream has abandoned the injunction against 'making graven images', Islam still adheres to it. In the Charlie Hebdo case, this meant that western cartoonists were 'deserving of death' for their portraits of Mohammed. In one of the attacks against that magazine, twelve people were killed.
From a ban on physical images, it is but one more step to a ban on mental images:
Quote“It is not permissible at all to imagine how the Entity of Allah or any of His Attributes is.”
-The late Shaykh Ibn ‘Uthaymeen, a prominent scholar of Islam
By way of contrast, we may look into Bernard Frischer's argument from The Sculpted Word: the early Epicureans were not only noted for their dedication toward portraits, but actually used them as a method for advocating the philosophy.