Suggestions for glass painting

[Cheryl Tyler]

I'm making an Internal window for a friends graduation present, her daughter
(six) loves to paint, so I would like to get a painting of hers (maybe get
her to paint onto the glass) and then build a window around the shape.

Any ideas for the best way of going about this. I was thinking something
like painting onto clear glass(thin), then placing another piece of clear
glass(also thin) over the top of the picture, and then leading around the
two pieces. Anyone got any horror stories about heat or damp ruining this
type of thing. It's still in embryo stage and I'm not sure how to pull it
together.

Suggestions appreciated.

Cheryl