The problem I have with the new policy is that I prefer thumbnails which show enough of the picture to inspire me to see the main picture. Generally, I use autogenerate for the thumbs, in some cases I crop the picture to show a closer view of the main figure. However, I think that in some cases I've gone too far. If I think the best thing about a picture is the overall composition, then I want to show that in a thumb. 

By banning nudity in thumbs, it makes it harder to show what the picture is about if the nudity is essentially incidental, but is difficult to crop out?