Blindsense: "Using nonvisual senses, such as acute smell or hearing, a creature with blindsense notices things it cannot see. The creature usually does not need to make Spot or Listen checks to pinpoint the location of a creature within range of its blindsense ability, provided that it has line of effect to that creature."
In this case, with multiple mirror images and distinguishing the real image, I'd have the familiar make an avg difficulty spot or listen check to accurately pin-point which image (especially when such images can be very close to one another). The difficulty with relaying said info is both an amusing and problematic situation however:
Psuedodragon: "There!"
Wizard: "Where!?"
Psd: "To your left, to your left!"
Wiz: "Aha!"
Psd: "No, your other left!"
Wiz: "Damn images, which one now, he moved?
Psd: Third one from the right I think and slightly off-center to...no wait, he's moving again, he's moving! There! The one that's pointing and casting, er, the second from the left now!"
Wiz: "&*%#@!!"
With images constantly shifting in combat it would be difficult for anyone to really pin-point the true image and relay this info to someone else. It'd be better for the Wiz to charge the Psuedodragon with a touch spell and have it go after the true image instead or just attack the true image so the Wiz could see which one.