Theme writing guide/tutorial

[Gabriele Greco <gabriele greco darts it>]

There is a guide not aimed to programmers about theme writing for GTK 
(I'm mostly intrested in pixbuf themes, but also a generic guide could 
be useful)?

I've to explain a graphic artist how to design a theme for a GTK 
application and what I've found till now it's too much "programmers 
oriented", but maybe I've not googled in the right direction :)

Bye,
 Gabry