I suspect the photos followed public opinion rather than led it. I think the negative photos of Viet Nam came more frequently as public opinion changed.
Also public opinion affect whether or not a picture is positively or negatively perceived. There have been plenty of pictures of the WOT that might have been viewed more negatively had the US not been attacked. Heck the loons on DU got mad at Bush over the photo of the soldier carrying the little girl at the top of this post.
.......and the duplicity plus cynicism of their propaganda against our president is so blatant. Their "message" is that if Bush hadn't gone into Iraq, children like this one would still be alive. Not so. Tens of thousands of children were brutally raped and murdered to fill Saddam's mass graves which now number in the several hundred thousand of victims. That would still be ongoing, if this courageous president hadn't taken the bull by the horns and ended Hussein's atrocities.