The friend's request is unreasonable. You don't own the rights to every photo that has ever been taken of you. That said, it's also a small request, so abiding by it shouldn't be a big imposition for the LW.

The LW doesn't seem to have the option of making her friend see reason on this issue. Her choices are (1) abide by the friend's request, or (2) don't, and deal with the possibly friendship-ending fallout. She can decide where her priorities lie. Personally, I would chalk this up to a personality quirk and modify my posting habits to preserve the friendship.