The amount of people who don't think Osama is dead is pretty small, from what I've gathered. Even in the Middle East, it seems that the large majority believe that the guy is actually dead. The people who don't think Osama is dead are most likely the people who aren't going to be convinced by pictures anyway. So, releasing the photos would most likely not convince the people they're intended to convince and quite possible end up pissing off and offending a crap load of people. On the other hand, I'm only human and am quite susceptible to morbid curiosity.