I'm engaged in the study of medicine and in modern medical textbooks there is very little (if any) restraint in what pictures they post of people and body parts. Ranging from very explicit diagrams, to real-life pictures of private organs, both living and otherwise, to pictures of cadavers etc...
I know the Rebbe opposed using cadavers for medical study but beyond that I'm not sure
My feeling is these pictures are not appropriate, but firstly it's very hard to avoid when studying the reproductive system etc.
OK, let's get one thing straight... I'm not a doctor (Psychotoddler, are you out there?), but I would be *highly* surprised to find that there exists any medical school in the United States that does not require a basic anatomy course which involves studying all parts of the human anatomy -- male and female. Furthermore, I would think that anyone who is intelligent enough to qualify for medical school would have known this going in.
If this is really a problem for you, then you shouldn't be studying medicine.
(Can you imagine what the state of medicine would be like if doctors could only study anatomy from pictures of *clothed* subjects? Can you imagine a gynecologist whose first look at a woman's vagina comes from his/her first patient?)