CSS Rounded Corners — Using only one image file!

There are lots of tutorials on this subject, yet most of the one’s you see require the use of four separate images, which means a lot of fiddly photoshop work; cutting, pasting, naming and saving — all times four.

This method will still need four divs, but it will utilise just one non-symmetrical image, aligned (i.e. not split) as indicated in this diagram: