Touhou 09.5: Shoot the Bullet

In Shoot the Bullet, you play as Aya Shameimaru as she photographs the bosses from various Touhou games. However, no one ever reveals the reason for these, and in fact at one point it is pointed out that "No one knows the purpose of the photos, except Aya", and the only reason she does not shoot the opponents is "not to be nice, but because she doesn't want her bullets in the picture."