Complex sentence: The photos were in fact collected by Sheldon to provide data for his ideas about somatotypes, although as "part of a facade or cover-up" the students and schools were told that the photos were taken to evaluate posture.
Split into simpler sentences: The photos were in fact collected by Sheldon to provide data for his ideas about somatotypes. However, as "part of a facade or cover-up" the students and schools were told that the photos were taken to evaluate posture.