So, the way this works is that you click on the resolution your computer is using, then right click on the image, go to Save Picture As, and save. Obviously. For Windows, to get to the desktop, minimize everything until you get to the actual desktop itself. Heh. Right click, go to Properties, and find the desktop you saved. If it's not on the list, click on Browse, and go hunt for it! :P Then click either OK or Apply, and it'll be there. :D If for some reason it doesn't work, or you have some feedback, contact me.
I realize a lot of people aren't using these resolutions anymore (myself included!) but I can't be bothered to make more desktops at the moment... so we'll see, I guess. For now, these will have to do.
Also, here are some desktop themes... these are actually embarrassingly old and bad, but I dunno, maybe you could just download them for the icons and then reset everything else back to default. But yeah, not only is there just the desktop, but icons, colored cursors, etc, etc, etc. Er, yeah. These were made for Windows at a resolution of 800x600, although other resolutions work as well. I'm not so sure about Macs, though. Eh. Anyway, I have two so far, one for the Elfstones desktop and the other for the Voyage one. Just... click on "Preview" to, well, preview it, and click on "Download" to... download. Yeah. XD By the way, you don't need to already have one of the desktops on the hard drive for this to work; the desktop is already included in the package.
Voyage Desktop: Preview! | Download!