I have a question about Islam, and the prophet Muhammed?

I seek to understand a few things, maybe the sensible Muslim people on here can enlighten me. I'm not trying to be an or incite anything, I really am curious about these things. If no one is allowed to draw a picture of Muhammed (or is it Mohammed?), then where did all of those ancient pictures of him come from? And if it's done to prevent worshiping him instead of Allah, then why are a lot of Muslims saying, "We are ready to die protecting the honor of our beloved Prophet Muhammad"? Doesn't that seem a little like worship to anyone else? And is it really THAT much of an affront to those of the Islamic faith, that so many feel the need to shout obscene remarks and threaten harm? Also, if you aren't allowed to have a picture of him, it seems contradictory to me to name your children after him. Also, what's the deal with Muhammed marrying a 6-year old girl and consummating the marriage when she was 9? Is that true, and... yeah,what's the reasoning behind that? I mean no disrespect, in any of this. I seek only understanding.