
So I find a picture of a rural scene since this home is out in the country (actually, if I'd been smart, I would have taken a picture through the window and the homeowner could have a very realistic idea of what the window would look like, if I'd been smart) and I make it a layer. I've made my drawing another layer on top of it.
I'll start with the border. Since the upper facet reflects what's below, I'll place the target of the Clone Tool on a section of the scene below the bevel (A above). Then I'll place cursor where the upper facet would be (B above) and click and drag to the right. The target will move in a corresponnding manner. This effectively "paint's" what the target is moving over into the area covered by the cursor.

Well, like I said, I'm using a poor man's version of Photoshop but I'd bet it has a similar feature.
j
http://www.homestudioartglass.com