Well not being in the right state to read Tl's complete answer to this thread, (which I usually tries to, cause he keeps one at ones toeas all the time ;) ) I would have to say:

Stupidity.
Superfuckingoverbelief that you think you are right to do whatvber you think is right.

I will add no more to this cause I know that there can be a hundred and one answers to justify it and to make it a henious crome all the same.

Lets just focus on one thing, what is "simply" the right thing to do with adding morale support or not.
Is it for example more right then to send videos of beheading an inocent to news media?

The coin is blodied and it had more then three sides...

It's called psychic numbing (sometimes referred to as 'emotional anesthiseia') - where an individual responds to traumatic events by blocking them out and erecting emotional barriers to create a sense of normalcy or disassociation from the events to which he is being subjected to.

They took photos because their personal 'mental self-defence mechanisms were activated' and so their minds told them that there was nothing wrong with what they were doing.

The hoods in some of the photos help to make the prisoners seem less human too - no faces, just bodies. Not human realy, so it's ok...