I hate taking pictures, even for my boyfriend.

Right now I'm in a long distance relationship with my boyfriend of around a year. Despite the whole bad rep of long distance relationships we are having no problems except for one: he really wants me to take somewhat dirty pictures ( as in pictures of me naked ) for him while he is away.

To an extent, I understand his needs. We're both EXTREMELY sexually active, to the point that a week is sometimes very sexually frustrating for us both. But we often enjoy a little time together over the phone if you know what I mean. The problem is, he claims that it's really, really hard for him to get off without seeing my body. And this is where the problems start.
I have never liked taking pictures. Not even NORMAL pictures. I don't have a facebook for this reason because I simply do not like the pressure of taking pictures at all. It's almost like a phobia. It makes me extremely nervous and stressed. Im also not very photogenic and pictures make me self conscious because it doesn't even slightly flatter me or my body. And I try telling him this but he really doesn't understand and keeps asking me to take them even though he says he'll stop bugging me about it.
Its not that I'm worried he will show anyone, or that they'll get around if I do take them. I trust him completely with that. He sends me some pictures randomly to show me that its not difficult (I never ask him for pictures because frankly, I don't need to see them.). He says sometimes that he understands and will wait because I tell him that I'm trying to get over it. It is like a phobia to me, and something I ask him for time to deal with but cannot vanish over night. But then less than a week later he's asking me again. He's extremely impatient.

Oh, and we're not teenagers. Im 21 and he is 23 and in the navy so he is constantly gone for long periods of time if that helps add any info. Any advice on this would be wonderful, and does anyone else feel the same about pictures? is it normal to feel this way?