Here's one difference! When a woman in the comic business criticized the image on the left (for being a a realistically-rendered minor-age character drawn with boob implants), she got buried in rape threats and attacked by many in her profession. Does that count?
As for the details of the images, if you need the points of comparison between them enumerated and explained in the first place, I don't think you'd accept that they were different from one another to begin with. Even leaving aside the issues of objectification, sexism, breast anatomy, selling sexualized minors to minors, or what it's a good idea to have your children aspire to (hello, context!) -- or the diversity of opinion between editors at Boing Boing -- some men will simply never see why the image on the left is even different from the image on the right.
But I would like anyone chancing across this to get to see them side-by-side.