Within a couple of hours, he produced this image with DotMatrix, a free Mac app. (That's why there's tacky advertising on it.) It's actually similar to what I'd envisioned, though there should be many more Earths, and of course it would have to be a higher-quality image. This would be the background for the cover.
(For those of you who haven't read The Worlds -- which is just about all of you -- the image is a hint as to the content of the book. I've been keeping the idea under wraps until publication. It won't be long until you can buy a copy and find out for yourself.)
Update: I've been reading The Worlds today and it's going well. However, I'm rewriting quite a bit of it. Everything can be improved, it seems. Because of this, I'm not zipping through the book. Editing is not reading. It's slowing me down. Actually, I have no idea when I'll be done but I'm enjoying the process, so it doesn't really matter. And in the end, I'll have a better book.
After that, it's time to address the cover problem.