For example, but not limited to, "Solo Female" makes logical sense for any image with one female character in it, but the tooltip defines it as specifically sexual. Also, the "Friendship is Magic" tag makes sense for any G4-related image, but is specific to the episode of that name (clearly shown as yellow after the edit, but during it looks like any other tag). To that end, it might also be helpful to have the tag colours in the editor too, but I'd settle for the tooltips alone.
It might also help to note in the tooltip which other tags are applied when one is added, to save time adding redundant entries. That's just a minor suggestion, though.