um, no, i don't think it already does that.  though i could be incorrect, i believe what it already does is show a default NUDITY/CENSORED thumb.  hence making everyone change their thumbnails so that these people could see the galleries without seeing  "unprofessional" censored thumbs and without actually changing the code.    at theartdoor, you just don't see nude thumbs until you enable them.  even if the thumbs don't have nudity.  so its' a seamless experience- you just see more pictures one way.  but you don't miss them if you're leave it on default.