Out of curiosity, is the hatsune_miku tag automatically supposed to go with all instances of hatsune_miku_(cosplay)? It's not implicated as such, but I see many people doing so. On the other hand, I don't quite think it fits due to Miku herself not being in all such images. (Though I do feel that vocaloid should still be included, as, even if Miku isn't in the image, it still becomes Vocaloid-related due to the cosplay.)