The way you presented the information, in my opinion, was wrong. The reason is that the Title first is an insult because of the sarcastic comment. Then you did not qualify the pictures. It's the same thing that the United States has done as well. When only the negative is shown time and time again, without mentioning anything good that they have done, or even suggesting that what you are showing is just a minority of the religion, a sweeping generalization has been made. It's not that you attacked Islam, it's how you did it.
Lets take this in another way. If I should some pictures of homosexuals robbing banks, and put the title as Peaceful homosexuals, I'm sure you would take offense, as you should. It is derogatory and would be out of line.
Eliot: I believe the reason that Islam has so many extreme members simply is because it is a relatively young religion. If you look at it's history though, it has calmed down to a point. Now, comparing it to Judaism or Christianity, both of those religions were also quite radical at one point. There was a lot of violence and hatred spewed forth from both religions in their early years. It is only recently that even Christianity has become more peaceful. So I believe that as the religion matures, it becomes more clam as well. Simply because the teachings become more accepted, and are made to fit the society in which they are living in.
Also, another large influence is simply the cultures that many Muslims come from. Culture has a lot to do with the radicalness that is presented in Islam. Many of the most Islamic countries are struggling. They are, for a lack of a better terminology, somewhat backwards still. Their education systems are not the best, and many are living in poverty and are simply ignorant. This leads to a higher susceptibility to be manipulated, especially if a charismatic leader can apparently prove that what they are saying is true.