Swarms and mirror image

[Lord Orion]

Ok...a pesky wizard has cast mirror image on himself. If I cast any of the swarm spells on him, (they do automatic damage), how does that affect the images? Do ALL the images take damage and vanish? None? Help!

[Dezhem]

None of the images vanish, as swarms don't roll to attack.

"Whenever you are attacked or are the target of a spell that requires an attack roll, there is a possibility that the attack targets one of your images instead."