Great, thanks. The pieces start to make sense. DeskShade messes with Desktops, allowing you to do all sorts of things with them. It likely cleared out the existing stuff so that it could manage it by itself. You have since deleted DeskShade, leaving you in your current quandary.
I am very pleased to hear that you have found the default desktop wallpaper. That means that DeskShade preserved the existing stuff as opposed to deleting it. I checked my Tiger install (same one, 10.4.11) and I don't have a folder called Apple Desktops. I would wager that DeskShade created this and dumped the original desktops in there to keep them, so that you could restore them later, perhaps through some form of uninstaller. I am not a user of DeskShade, so I am not sure of its uninstall approach.
Can you look in the Apple Desktops folder and see if all the other standard desktop backgrounds are there? There should be around 28 to 30 items there. If they are there, recovery from your problem should be as simple as moving them back to /Macintosh HD/Library/Desktop Pictures.
Because these are system files, you *may* not be able to just drag and drop, but do try this first. If you are not allowed to, you will need to use Terminal.app to do this job. To do that, issue this string of commands from the Terminal.app window:
Code:
cd "pathname-of Apple Desktops folder"
sudo cp * /Library/Desktop\ Pictures
That's it. Of course, you will need to replace the "pathname-of Apple Desktops folder" with the path name to that folder, wherever it is. And, after the "sudo cp" command, Terminal.app will prompt you for your administrator password, which you will have to enter.
That should do it. Your desktop backgrounds should now appear in the preference panel. Good luck!