R.D.
'She sent me an email asking her to email her specific picture files for this purpose, never asking it was okay if she used my pictures'...
So she asked for the pictures to use, but didn't ask your direct permission? To me, it seems like you gave her permission by sending her the pictures. So yeah, to be honest, I can't see how/why you would be upset.
Besides, how bad it is really?! There's a really nice gesture behind it, so what's the problem? Are you upset you didn't think of this first?
(I'm really not trying to be blunt, I honestly don't see the issue here).