A lot of people think that picture book authors sit down with their illustrators and discuss their vision of their story. This is not how its done.
I would never have even met my illustrator, Olivier Dunrea, if I had not dragged myself and my huge pregnant belly down to Books of Wonder one day when he happened to be doing a signing there (and when I say huge, I am NOT frickin' kidding.)
The norm is for there to be no contact at all. Seem counter- intuitive?
I guess the theory is that the illustrator should not be unduly influenced. It is his or her job to come up with the visual expression of the story and the author just has to trust them to do exactly that.
I certainly wouldn't tell my OB-GYN how to do his job. But there is something very difficult about giving up all control to the illustrator. I guess that's why someone invented "art notes."