I find it ironic how traditional Muslims get offended when the prophets image is/gets depicted, yet when the very sources (i.e. Hadith) which they hold dearly depict him in a despicable way (such as claiming he married a 9 year old) they neither take offense to it, nor question it; hypocrisy at its finest.
Now me, personally, I take no offense to it, even when the intent of depicting him is to insult. If someone drew the prophet in an ugly and unpleasing way, I wouldn't take offense to such because for me the question is/would be: how could said artist know the way in which the prophet looked? Surely he wasn't alive during that time, nor where cameras available during that time. Thus I (would) dismiss such depictions on the basis of 'lack of evidence'.