When Demi, an award-winning author-illustrator of religious children's books, set out to create "Muhammad," she had no idea depicting Islam's prophet was considered idol worship, a grievous sin.

So after consulting a Muslim teacher, the author used gold leaf to represent Muhammad's outline, creating a silhouette that is beautiful yet respectful of Muslim beliefs.

Global outrage and violence over insulting cartoons of Muhammad reveal just how inflammatory portrayals of the prophet can be. So to avoid controversy, visual artists like Demi have long found creative alternatives. The techniques range from blotting out Muhammad's face in medieval manuscripts to shooting contemporary films from his vantage point.

History proves, however, that passions can still erupt even when artists go to great lengths to avoid offending.

Nothing in the Qur’an forbids representations of Muhammad. But the Hadith, a collection of sayings and actions attributed to the prophet and his closest companions, explicitly condemns such depictions, as well as pictures in general. The problem is two-fold: fear that pictures could become objects of veneration, thus constituting idol worship and concern that creating images mimics an act of God.

The restriction gained fresh appeal during the Crusades, when Muslims wanted to differentiate themselves from Christians, and viewed depictions of Jesus as leading to idol worship. Over time, Muslims have come to take the prohibition more seriously, pushing today's artists to find visual alternatives.

"Not only has it become very solidified and strengthened, it really has become an article of faith," said Khaled Abou El Fadl, an Islamic legal scholar at UCLA Law School, speaking of the prohibition on images.

Moustapha Akkad, a Syrian filmmaker and observant Muslim perhaps best known for producing the "Halloween" series of horror films, did not show Muhammad's face in "The Message," his 1976 film about the prophet. Instead, he shot the film from Muhammad's perspective, so at times it seems as if
characters are addressing the viewer.

Still, the film reaped denunciations and bomb threats while in the making, compelling Akkad--who was one of dozens killed in terror attacks in Amman, Jordan last November--to seek blessings for his project from scholars at Al-Azhar University in Cairo, as well as other religious institutions.

Nonetheless, the film's release provoked black Muslims from the heterodox Nation of Islam to take dozens of hostages in Washington in a failed effort to stop its distribution.