I couldn't find a topic about this but cosplay photos are a very small percentage of the images on the site so it would make sense.
Do photos where the cosplayer is (presumably or known to be) a different gender than the character get tagged as the person's gender or the character's?
post #81128 was tagged with 1girl which would technically make the genderswap tag applicable but it's not exactly relevant. post #106723 was tagged with 1girl and crossdressing which also isn't exactly relevant. To me it would make sense that since the character is the focus of the image and not the cosplayer, both of those should be 1boy.