I am uncomfortable about students taking pictures of the blackboard, because I don't like appearing in them It seems to be the trend that fewer and fewer students take notes in class. Lately, and particularly this semester, for some reason, I have been noticing that several students take pictures of the blackboards with their phones in lieu of taking notes.

While I'm not necessarily against this, if it helps them focus on class, I'm uncomfortable about being in a million pictures by these students. I'd like to speak up, but it's already a few weeks into the semester, and I don't want to make the students feel uncomfortable either. Is there anything that I can do to resolve this without creating discomfort on either side?
Perhaps you could make an announcement that just before erasing the board, you will pause for a moment to allow pictures to be taken, while you stand out of the way so as not to obstruct the shot.  You can ask photographers to wait until that time, and to please compose their shots to exclude you if necessary.