OK, first of all, I got permission from all of the people I photographed. In the cases of underage cosplayers, I got permission from their parents as well. Please don't use these for any kind of commercial purpose, or claim them as your own photos.
Second, be warned that while all of the costumes are work-safe, a couple of them reference things (like M-rated games) that aren't quite meant for kids.
Here are the photos I took at DragonCon, sorted by costume type. And yes, there are Monster High and MLP folders in there.