premise: There is a woman in a black jacket and sunglasses and a man in a white shirt with his back turned. hypothesis: A man turns his back just as he and a women were about to get their picture taken.
neutral: There is no reason given why the man turns his back. One cannot infer that he purposely or accidentally turns his back. There is no mention of photographing anyone, so the inference of getting their picture taken is not valid. It is impossible to infer at what instant the man turned his back, so the time indication of "just as" is an invalid inference.