Well, I'm glad wikipedia's sticking to their guns on this issue:

More than 180,000 worldwide have joined an online protest claiming the images, shown on European-language pages and taken from Persian and Ottoman miniatures dating from the 14th, 15th and 16th centuries, are offensive to Islam, which prohibits any representation of Muhammad. But the defiant editors of the encyclopaedia insist they will not bow to pressure and say anyone objecting to the controversial images can simply adjust their computers so they do not have to look at them.

The images at the centre of the protest appear on most of the European versions of the web encyclopaedia, though not on Arabic sites. On two of the images, Muhammad's face is veiled, a practice followed in Islamic art since the 16th century. But on two others, one from 1315, which is the earliest surviving depiction of the prophet, and the other from the 15th century, his face is shown. Some protesters are claiming the pictures have been posted simply to 'bait' and 'insult' Muslims and argue the least Wikipedia can do is blur or blank out the faces.
Rest: LINK

I guess it's hard to riot while sitting behind a computer.