I think what they mean is that by increasing the contrast on the left picture many features stand out more, like the lips, and a lot of shadows "blend in" the f

I think what they mean is that by increasing the contrast on the left picture many features stand out more, like the lips, and a lot of shadows "blend in" the face, which in turn makes it look smoother and rounder. Both of these characteristics are interpreted as more feminine. In the second picture you are able to distinguish a lot more shadows and that seems like a "stronger" bone structure. (When I say stronger in the last sentence I mean with more extrusions etc but I cant think of the correct word right now, sorry)