Hi!
Here are the forum's Community Guidelines.
Since this is open forum for anyone, including underage people, anything that could be considered explicit is not allowed.
Only artistic nudity is allowed. The difference is in the purpose of the artpiece. If you're not sure whether it could be considered artistic nudity or not, it's best to be on the safe side and not post it.
If any forum user flags a post they think it's inappropriate and/or moderator judges it inappropriate, it will get removed. (The flags stay on the poster's' profile to let us see who's a repeated offender.)
Rough rule of thumb If it's something that a child could see in a classical art museum, it's probably ok, otherwise it's better to not post it.
Hope this answers your question!