They are enemy soldiers that fired upon American forces. Not terrorists, but not innocent either. Doesn't mean they should get such horrible treatment, though.Oh god... They haven't even been tried. NONE of these people are convicted terrorists, and therefore you shouldn't be calling them terrorists.
As for the claim - no, the actual images of the despicable acts at Abu Gharaib should not be released. There's no reason to - it would harm the prisoners even more, would make people sick, and doesn't contriubute to anything. The acts have been made, no-one is denying that, and so, actual images are not needed.
If anyone asks for these images and videos to be released, I'd have to doubt their motives, thinking maybe they're from rotten.com, or own some tabloid that could profit from such disgusting images.