[Daring Scylla]

in the art classes i've been in and in the study of art itself, tasteful nudity generally means that while nudity is a part of the composition, it's not necessarily the focus of it or if it is, it is a focus on the beauty of the human body, such as the romanticism era in art (like botticelli or michelangelo - both heavily studied and admired the human form but in a more romantic way, not in a pornographic way)
people's definitions of 'tasteful' are going to vary, so you might want to put a little start like, next to it and mention 'here is MY definition of tasteful nudity" so people will know exactly where you coming from
in any case, pornography or pornographic images usually doesn't fall under the "tasteful nudity" category, but you can have genitalia showing without it being considered pornographic.