From How images of the prophet Muhammad became ‘forbidden’ – The Washington Post:

It’s so commonly reported that Islam forbids Muhammad’s portraiture that it seems almost a waste of space to repeat it. After all, isn’t that why some Muslims were so outraged in 2006 when the Danish daily Jyllands-Posten depicted Muhammad in an unflattering light? Isn’t that why the Metropolitan Museum of Art pulled three paintings of the prophet? Isn’t that why the TV show South Park had to censor all mentions of Muhammad in a 2010 episode?  “Islam forbids images of Muhammad,” CNN boomed in a headline last week.

But the reality is substantially more complicated. The Koran, in fact, does not directly forbid the portrayal of Muhammad. And the second most important Islamic text, the Hadith, “presents us with an ambiguous picture at best,” wrote Christine Gruber of the University of Michigan. “At turns we read of artists who dared to breathe life into their figures and, at others, of pillows ornamented with figural imagery.” The most explicit fatwa banning the portrayal of Muhammad, she notes, isn’t tucked into some ancient text. It arrived in 2001. And its creator was the Taliban. The ban is a very modern construct.