Backgrounds

I need some very good-looking backgrounds for my game, but I don't want them to slow the game down. I tried using pre-rendered images and scrolling them across the screen in the distance, but they looked (not surprisingly) like flat images.

Is there another way I can have very high-quality backgrounds that won't slow mu game down to a crawl?

With this method you can only make the background look like it is far away, you need to make it follow the camera, and set the drawing order for the background to be the highest, so that it will be drawn first, I hope that will make a suitable background.