The left hand and the right hand are 'mirror images' (of each other). = The left hand is the/a 'mirror image' of the right hand.
He's the 'mirror image' [=(more commonly) 'spitting image'] of his father. [=he looks just like his father]
She is worried about what motherhood will do to her 'image' [='reputation'] as a rock star.
(..) - No, I'm working. why I just kept you alive? Yes. That is not the true eye. - This is the true eye. - It's not, actually. It's a mirror image. Miss Croft, I think you're trying to cheat me out of my little ray of sunshine. Why would I try to cheat you out of anything now? I need you (..)2001 Lara Croft: Tomb Raider