I remember about 10 years ago there was a big scandal in the US when it was discovered that one of the leading university had in its files naked photos of their students, some of them having become proeminent people, taken as part of the medical exams they had gone through.
Those photos you are referring to were part of a very serious long term study which was meant to determine the correlation between body posture, type and intellectual capacity for achievement in later life. The postulated thesis being that ideal physical characteristics of one's body tend to give a person intellectual and personal advantages in (the struggle for) life.
Simply put it was a twist on the idea that the better looking you were physically, the more you would achieve as a person. Naturally the jargon used was much much more complex than this and the argumentation was given in scientific terms along with many complex and intriguing examples of human physical types. In the early 20th century, this idea was taken quite seriously in many scientific circles. Taken to it's logical conclusion, it also lead to the study of comparative physical characteristics of what was then called the different human races - now referred to as ethnicities.
You can still find very nicely published books from that time showing detailed diagrams, drawings and photos of nude people from various places on earth, taken for the purpose of making comparisons of body build and structure. In many ways such books were little more than porn for the higher classes, but they do reflect a mind set that is typical of the times.
In the US apparently some universities were talked into participating in similar studies, with students being photographed nude and classified into various body types. The idea being to see if there was a correlation between future achievements and their physical appearance.
I'm not certain any results were ever published or even made based on these nude posture photos.
You can find a number of articles on this intriguing and interesting, if debunked subject. Here are a few: