Some Muslims complain that this cover is an insult to their religion, which forbids any depiction of of Mohamed, and they suggest that Charlie Hebdo acted immorally in publishing it. For example, Egypt's Grand Mufti complained about the publication of the above drawing (see quote below). Their outrage is completely absurd, and should be completely disregarded.
Muslims have every right to practice their religion as they see fit. If they do not wish to create or view images of Mohamed, that is certainly their prerogative. No one should force them to do so.
Under no circumstances, however, do they have any right to tell anyone else not to make or view such images, any more than a Jew has the right to tell a Christian not to eat pork or not to drive to the store on Saturday. If a Jew sees a Christian driving to work on a Saturday, eating a McRib sandwich and gets offended, that is his problem.
Ironically, the Koran and the Hadith contain statements that I find extremely offensive. For example, they state that homosexuals should be killed, and that women must be subordinate to men. Muslims assert that these dictates are the word of God.
I find parts of the Koran and the Hadith to be utterly ridiculous, and I find the claim that these are the words of God to be very offensive. As a result, I do not read the Koran or other Islamic literature, and I certainly do not practice Islam. But I do not tell others what to do.
I do not warn Muslims not to publish the Koran or other religious books with material that I find offensive because of my sensitivities. Quite to the contrary, I know that people will disagree about all sorts of things, and I am happy to live in peace with anyone who will allow me to do so. I do not seek to force others to live by my views, nor to live the way I live. But I expect the same respect in return.
So let's compare: Charlie Hebdo publishes the image above, and Muslims (some of them) are outraged. These same people repeatedly proclaim that a book that says I should be killed as the word of God, and they see no problem with that. And, even worse, some non-Muslims in the West sympathize with their offense. But that is for another day.
Quote from the Grand Mufti of Egypt, copied from Huffington Post:
"This edition will cause a new wave of hatred in French and Western society in general and what the magazine is doing does not serve coexistence or a dialog between civilisations," the office of Grand Mufti Shawqi Allam, one of the region's most influential Muslim clerics, said in a statement.
"This is an unwarranted provocation against the feelings of ... Muslims around the world."