How can I set desktop background color via .bat file?

:/

I tried what you suggested and it didn't seem to work.  Also, I tried using the %UserProfile% and that didn't work either, I had to go back to my %USERNAME% in order to make my old stuff work.

The cheesy workaround I did, is what my boss suggested, which is simply make the image HUGE.  This works, but results in a very large image size.

Any further help would be great. :)

The easiest way to do this is by using Windows "Themes".  This is installed in XP by default, and creates a file association with the *.theme file type in the registry.  Files with the *.theme extension will open on a double-click straight to the Desktop Properties "Themes" tab.

The command that is run is:

%SystemRoot%\system32\rundll32.exe %SystemRoot%\system32\shell32.dll,Control_RunDLL %SystemRoot%\system32\desk.cpl desk,@Themes /Action:OpenTheme /file:"Filename.theme"

where "Filename.theme" is the file containing the settings.  A *.theme file is just a text-based file with section headers like an *.ini file.  It's file to edit in Notepad, but there is no need to, because whenever you change something away from whatever "theme" you currently have set, it then allows you to do a "Save As" from the "Themes" tab without actually applying the changed settings at that time.

Let me show you with screenshots.  I just use the "Windows Classic" theme because I find the big pastel-shaded borders of the "Windows XP" theme a bit too much like a child's nursery and toys.

All I did was open the Desktop Properties to the "Desktop" tab, and change the background colour to a sickly shade of green.  I DID NOT click the "Apply" button, but instead went to the "Themes" tab and you will see that it now showed the current theme as "Windows Classic (modified)".  From there you can just do a "Save As" and choose a destination and file name for your *.theme file.

The default location for *.theme files is the:
C:\WINDOWS\Resources\Themes
folder, and you would there find "Windows Classic.theme" and "Luna.theme".

If you saved your new custom *.theme file to that folder, then it would be available in the drop-down "Theme" list under the Desktop Properties > Themes tab for selection.  That, however, is not the purpose of this particular suggestion.

Double-clicking on your modified *.theme file would open Desktop properties to the new Theme and allow you to click the "Apply" button and make an immediate change to the desktop.

The drawback with writing values to the registry is that this type of change is not applied until the user logs off and back on again.  Even refreshing the desktop, or killing and restarting explorer.exe does not apply the change after changing registry values.  Of course, you could add a command to log the current user out, or restart the system, or whatever, but that's not the best method really.

Damn, I pressed a key somewhere that acted as the "Enter" button while I was trying to insert a paragraph at the top of my comment, which was going to be:

If you just want the Desktop to be black, then you don't need to use a Wallpaper image.  You can just set the Desktop Color.

I hadn't finished my comment either.  It will continue in the next comment.

Forgot the *.theme file renamed as a *.txt file, didn't I.

OK, if someone can fix my attempt at a *.vbs script so it gets past the path to the *.theme file, then this would be a better way.  See code snippet.  The error is at the   "C   part on this line:
/File:"C:\WINDOWS\Resources\Themes\Classic_Black.theme""

Someone else seems to have a fully functional script here:
http://blogs.msdn.com/alejacma/archive/2008/11/26/how-to-change-windows-theme-programmatically-in-xp.aspx
but I haven't tested that.

' ChangeTheme.vbs
' Usage wscript changetheme.vbs
 
' Create the program environment 
Set WshShell = WScript.CreateObject("WScript.Shell")
 
' Load named .theme file into Themes tab of Desktop Properties
WshShell.Run "rundll32.exe Shell32.dll,Control_RunDLL desk.cpl desk,@Themes /Action:OpenTheme /File:"C:\WINDOWS\Resources\Themes\Classic_Black.theme""
 
' Pause for 2 seconds, ie. 2000 milliseconds for it to load
Wscript.Sleep 2000
 
' Make sure Desktop Properties dialog stays in focus
' to receive the keystrokes to be sent to it.
WshShell.AppActivate("Desktop Properties")
 
' Click the Apply button using Alt and A keys
WshShell.Sendkeys "%{A}"
 
' Pause for 7 seconds for the changes to be applied behind the dialog
Wscript.Sleep 7000
 
' Make sure Desktop Properties dialog stays in focus
' to receive the keystrokes to be sent to it.
WshShell.AppActivate("Desktop Properties")
 
' Click the OK button, which is the same as Enter, to close dialog
WshShell.Sendkeys "{ENTER}"

                                              

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Yeah, that other guy's script works fine on my XP SP3 system.  Just set the path to your *.theme file near the top of the script.