I recently wrote a gadget to view APOD on the desktop (that background-replacing program is a bit overkill for something like APOD, don't you think?), and RJN said I could distribute it, so here it is.
Some screenshots:
With transparency enabled:
The explanation is displayed when the picture is clicked (Click again to hide it):
Installation Instructions:
(Gadgets only work on Windows Vista and above.)
Once you download the .gadget file and open it, you'll see a security warning pop up asking if the gadget should be installed:
Click install, and the gadget should show up on your desktop. It should work correctly, updating it every day automatically - at least, it has been for several days on my computer - but if you find any problems, message me and I'll try to fix it as soon as possible.
Known Issues:
This is my first attempt at building gadgets, so I haven't been able to resolve all the problems yet. Some of the local hyperlinks (i.e., "/apod.rss"; "lib/edlinks.html"), for example, may not work properly because the gadget HTML parser thinks links to "foo.bar" and "/foo.bar" are the same; the image tooltip (the picture title, displayed when you hover over the image) doesn't bother showing up half the time; and it seems virtually impossible to make the explanation text work with correctly with a transparent background, like how Windows itself does it:
(that text with the glow: 'tis impossible magic, that's what it is. It's perfectly possible with normal text, but with a HTML input, it suddenly becomes a bunch of magenta-colored gobbledygook.)
If you know how to fix these, could you please message me?