Fact-checker request

Writing about the cartoon brouhaha in today's Opinion Journal, Muslim (I think Persian) Amir Taheri writes:

There is no Quranic injunction against images, whether of Muhammad or anyone else. When it spread into the Levant, Islam came into contact with a version of Christianity that was militantly iconoclastic. As a result some Muslim theologians, at a time when Islam still had an organic theology, issued "fatwas" against any depiction of the Godhead.

I have no animosity toward Taheri, and I hope his assessment of Islam is true, but I've always heard the influence of iconoclasm as going from Islam to Christianity. Which is it? Could it be both? (I've observed these confluent streams in many areas, from philosophy to politics to baby names.) Can anyone suggest any good source material where I could look it up?