There are automated crawlers that can do that. I have had many problems with users posting copyrighted images of famous people...I think in the real world, photo issues amount to a hill of beans. Just my opinion. With all the photos posted on VS web sites, I doubt they have a team of lawyers tracking every photo.
Also i want to point out something here (as a former forum founder/owner).
No matter what VS says, the content is still yours and you can post it on other places if you want.
What you can not do is ask them to remove it, they as forum owners have the right to use it in their website(s).
Also, if the terms are changed over time, the rules that where in effect at the time of the post/image placement prevail.
So any existing content can not just be " stolen" from you.
That is, according to dutch law...