That's why I prefer Wmii, Ion2 and similar window managers. They really manage my windows, ensuring that they don't overlap and use the screen effectively.
In contrast, most other window managers just enable you to fiddle with the windows yourself, and that's all they do for you. You keep moving and resizing them, one by one, steadily. That's very annoying.
(In fact, I don't even have a desktop image, because most of the time, the desktop isn't visible anyway. I don't want to look at my desktop, I want to use that space for the application I'm working with!)