I don't think killing somebody for any reason can save Islam. Why should we worry trying to save something that is bigger and stronger than us? A rude comic about Muhammad wont change our love to him. I even 100% sure, it wont change how other religion respect Islam and Muhammad.
However, killing in the name of Islam can create hatred to us, as muslims. We are losing respect. Now I am scared the society feared us.
Should I change my religion so that people wont hate me? No I wont. I just need to tell the world that Islam is a kind religion. That is why I am a muslim. The terrorist are just a few muslims who read Quran without their heart and soul.
As a muslim, I am deeply sorry for what happened to the cartoonists and the policemen in Charlie Hebdo, Paris. They are heroes for freedom of speech. I wish their soul rest in peace.