Augustine was wrong! I suspect that the reason he went the route of women not being fully the image of God, aside from his patriarchal frame of reference, was that the church is the bride of Christ, and apart from Christ can't reflect the glory of God. But those two don't have to be, in fact, shouldn't be, tied together.
The problem with Augustine is that he wrote so much that you can find pretty much anything you want in there. Unfortunately, it seems his worst stuff is what the church adopted! But that is just an