I have mirror image in my wizard, thanks to a legendary goblin with trickster. But it will be easier to jasper a rogue weapon, or jewel, with trickster on it instead of ambering your weapon. That way, with every command\skulldra cast you will get a mirror image. I use command lvl 33 and I can gather up to three mirror images by casting it.
By the way, summon increases your summon’s stats (including mirror images), not your, unless you are using a synergy hat. Skullshield lowers damage and shoots to any enemy. Since both summon and skullshield are available in talent form (reclaim & recall), go with a tome (the void tome is pretty good), command is more useful than skulldra.