I have often wondered where Leopard (OSX) stores the stock Wallpapers available in the Desktop Option in System Preferences. A bit of digging led me to the location.

/Volumes/’YourMacHD’/Library/Desktop Pictures/

Where ‘YourMacHD’ is the volume on which OSX is installed. I was rather surprised at first that it wasn’t under the ~ set of folders. But yeah it does make sense, it is after all a systemwide implementation/feature.