Talked to a law professor friend about this and he seems to think that while not technically legal, the law hasn't really settled a case that deals with someone disseminating something on a public forum and then it going viral. He said he believes that since it's a public space and Internet users should be aware of the viral nature of the medium, they typically would not have recourse -- until someone actually sues to have their material taken down on other websites (which obviously is a lengthy process).
Basically, websites know it takes a long time to get people to take this stuff down, and since it happened in public and was posted on a public forum, the "illegal" nature of taking it and using it on other websites is lessened.
The "virality" idea is interesting...but from a pure copyright perspective, I take a different view.
And I don't think it matters whether the medium in which the photo appears is online, print, TV or anything else.
We're getting really hypothetical now but...suppose instead of wanting his photo withdrawn, Orange46R wanted to be paid for his work.
It seems to me Sports Illustrated (and other infringers) would have to work out a deal (or force him to sue).
One of my favorite cases is largely on point...the case of Hugo Zachini the Human Cannonball.
(I link to the trailer because it's obviously posted for promotional reasons).
The trailer only has a few good seconds beginning at about :55 in.
But that makes the point.
The guy had a brief limited act.
A TV station couldn't show the whole thing...it all but destroyed Hugo's right and ability to make money from his performance.
Same thing with the photo of the woman at the Indiana game.
You can't just steal it...That photo is the entire work.
Using it destroys the copyright holder's right to profit from it (not that Orange46R ever would want to do that).
Another good example is the way helicopter pilot Bob Tur enforced his rights to the video he shot of thugs beating up truck driver Reginald Denny during LA's Rodney King riots.
He sued.
People stopped swiping his video.