Hello,
The more I think about it (and look at the examples) the less clear the folders are to me.
If a single figure is bound, but other figures are present, does it go into Solo Male/Solo Female? Or into one of the other folders? Or is it "it depends"?
What is "Male and Female" intended for? Two bound figures, one of each gender? Captive plus captor, one of each gender? Both?
Is "Bondage Couple or Groups" for all art with two or more bound figures? For two or more bound figures who are not showing "interest" in each other? (Because if they are showing "interest" it should go into Gay and Yaoi or Lesbian and Yuri or Male and Female instead, as appropriate.)