php/ajax slideshow

javascript slide shows can be a useful, quick
and dirty way to display a small collection of images.

But javascript slide shows typically want to download
a whole directory full of images before they begin
(body onlLoad="startshow.js")

But it seems entirely possible to combine asynchronous
ajax requests with php session variables, so a slide
show would download the first ten images only, and
immediately commence showing those ten, while another
header request trips out to the server to get the next
ten images.

I looked around for such a script, but couldn't find it.

A) anybody know of a precanned script that does this?

B) if not, am I missing something? Is this a fatally flawed idea?
Would it be a big
mistake to try to write this?

Ooops. Sorry to waste bandwidth.
There are several good php/ajax slideshows out there already.
(it was a good idea)