[gwd]

> how do you know if the image that just generated is substantially similar to an existing copyright work?

This is already a problem with biological neural nets (i.e. humans). I remember as a teenager writing a simple song on the piano, and playing it for my mom; she said, "You didn't write that -- that's Gilligan's Island!" And indeed it was. If I had made a record and sold it, whoever owned the rights to the Gilligan's Island theme song could have sued me for it, and they would (rightly) have won.

There's already loads of case law about this; the same thing would apply to AI.

> what is stopping someone from generating millions of images and copy righting all the "unique" ones? Such that no one can create anything without accidental collisions.

Right now what's stopping it is that only humans can make copyrightable material; whatever is spat out from a computer is effectively public domain, not copyrighted.