Pictures of trees with vinyl window screen used as drainage, or the screen itself? If the later, look at your window. If the former, I hope you're not calling my integrity/trustworthiness into question. I have no reason to lie about this. I'm just telling you the way it is from my experience and from what I know to be the case.
Unfortunately I have no camera, and the nursery I speak of is in Maine and I'm in Vermont at the moment. Perhaps sometime in the unforseeable future I could post picture here though. I do plan on getting that digital camera I so crave...someday.
I'm willing to try a more coarse holed mesh though. Couldn't hurt, and maybe I'll even become a convert. As-is I have no basis of comparison, and can only say I've had no problems with drainage with window screening.
Regards,
Toby