I'm on a site called Purpleport where photographers and models can connect. When you upload an image there is a check box for NSFW which is the default and if you are uploading SFW images you can untick it. So anyone looking at the site can only see SFW images and only if they choose to see NSFW images by selecting the show NSFW images filter from a drop-down do they become viewable.
Could something like this be incorporated in the new site? Art nude is a genuine photographic genre and one that I shoot a lot of but I've shied away from posting any on my profile. I'll have to dig some out. Feel free to let me know if they are not welcome.