Allah defend his Prophet against portraying him and muslims as a terrorist:
"Shall We then treat those who have surrendered as We treat the guilty? (35) What aileth you? How foolishly ye judge! (36) Or have you a book you learn from ? (37)". (Quran 63)
And also invites people to islam:
"O people of the Scripture! Indeed Our (Prophetic) Messenger has come to you, expounding to you much of that which you used to hide in the Scripture, and forgiving much. Undoubtedly, there has come to you light from Allah and a clear Scripture." (Quran 5:15)

So here you can see how Allah (God) defend his beloved Prophet and muslims from cartoons and caricatures.
Quran tell non-muslims that it's not good to learn about Islam from some books full of lies, but they must keep searching after the truth. They don't have to judge muslims with only what they listen and read, because in that case the judgment will not be just.

Allah describe his prophet in many versets in quran. The Almighty says in The Holy Quran:
"By the grace of Allah, you are gentle towards the people; if you had been stern and harsh-hearted, they would have dispersed from round about you." (Quran, 3:159)
"O you who believe! Ask blessings on him and salute him with a worthy salutation." (Quran, 33:56)
"And We have sent you not except as a mercy for all the worlds." (Quran, 21:107)

You can find more in Muhammad qualities.