Guide on how to add themes / presets

Hey, I wanna generate a bunch of themes, but would appreciate a guide(or a .cursor/rules file), where I can just send vibes / general ideas / screenshots of the websites, and it will generate a theme for me.

I know that I can do that manually, but I am probably not that well equipped for modifying it manually, all I want is just send a bunch of screenshots, therefore asking for an AI friendly guide :)

Thanks!