Hmm.. thinking about it I was also intrigued by this kind of answer well, if Anna doesn't need to like sending these photos to Chris why does she do it then?
That's the question maybe it has to do with Anna's sexual frustration high libido the lack of sex with David too and in this kind of situation Anna found something to distract her like sending sexy photos to her husband's best friend because then maybe Anna manages to get rid of the discomfort and the bad feeling of all these problems and sending these photos maybe she has fun or not or it's just something to please Chris and Anna herself it's hard to understand this without knowing the expectation very well her at the moment.