You can change your Desktop background image in a variety of ways…most of which require you to launch your System Preferences an use the Desktop Preferences panel, but – with Safari 3 – there is a much quicker way to do this.
Simply take any image that you want to use for your Desktop Image, and drag it to your Safari 3 icon. The image will open in Safari, and you can control-click it and select Use Image as Desktop Picture from the pop-up menu.
Note: This works in Safari 3 only. It will not work in previous versions of the browser.
Thanks to Jeff for sending this in!