Before my husband and I got married, we were living in different cities and I sent him a sexy but demure self snapshot in an email ("sexy but demure" means I was naked but you couldn't really see anything, I was standing mostly behind a door so you only saw the very right edge of my body). He liked that so I sent him another where I was a little bit less hidden. (My roommate had served as photographer -- and, yes, I did take pictures of her that she sent to her boyfriend.)
Eventually he received one where I am standing fully nude and fully pictured in the open doorway. He loved that one too. He returned the favor by sometimes sending me pictures he'd taken of himself with his camera and a mirror. I liked them. The funny thing is, that although we both had digital cameras, I can't recall using them to take nude pictures together (you know, really sexy pictures where we are pleasuring each other) until after we were married.
One time, a few years ago, I had to be away on a week-long business trip and I left him a surprise present -- I had used our camcorder and taped myself stripping for him. These days we find that modern communications technology have reduced the need for business travel but each of us sometimes must still be out of town for a few days. I sometimes use a digital camera to take nude pictures of myself in my hotel room and send them to him at home and he sometimes does the same when he is away. We are always careful to use our personal e-mail addresses rather than corporate ones and to carefully erase any images from our work laptops as soon as we send them. (Seriously, you should all be very careful about that.)
I enjoy knowing that my honey is looking at a nude picture of me. I also like others looking at me which is why I sent you my photo. I also like looking at nude pictures of him and knowing that he was thinking about me (and in some of those pictures it is really obvious what he is thinking about! Hee!)