I can't believe I didn't notice this sooner, but images and videos have different sets of "category" checkboxes. I understand that most people don't properly use the category system but, a bug is a bug and it should be fixed. Most of the categories are shared but these are the differences:
Image posts can have the "Tutorial" category, but video posts cannot.
Video posts can have the "Honey Select", "Source FilmMaker", and "Virtual Youtuber" categories, but image posts cannot.
Please fix this bug so I can properly tag my Vtubers images, and so other people can properly tag their Tutorial videos!