[Jmenschenfresser]

Well, you can use Povay and its compliment Moray. I only looked at doga for a few seconds and it seems easier to use than povay is. But moray and povay come with good tutorials so an hour a day for a week can result in you fairing pretty well.

Of course you can cut images you find on the net. Or you can free hand your own with a paint program, if you don't mind its crudeness. If you really want something decent looking I'd go with the Povay/Moray combo.

Povay is a raytracer program. (I think that's what it is called), but you have to spend a little time learning the scripts to get what you want. Not at all hard, but a steeper learning curve. Moray is a graphical interface for Povay. It is shareware, I think. Povay is freeware. With moray you create objects and resize them, move them, and create color maps for them. I'm personally not very good with the color maps. All mine turn out looking like some kinda strange timber.