Add/Change a Windows XP Logon Wallpaper...
1) Navigate to:
HKEY USERS\ .DEFAULT\Control Panel\Desktop
2) Double click the wallpaper value, and type in the full path of your image and the filename (i.e. This could be your favourite image or picture as long as it is a .bmp or .jpg).
3) To tile the image set "TileWallpaper" to 1
4) To Stretch the wallpaper set "WallPaperStyle" " to 2
5) Close the Registry editor (i.e Regedit.exe) and the changes will take place when you Log off.
IMPORTANT: This procedure contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article numbers to view the Microsoft Knowledge Base articles:
The above trick may not work when you have the Windows XP welcome screen configuration, but you can easily turn off the XP welcome screen.
I personally prefer the "Log On" screen - (NB - If you are using Windows XP Professional on a "domain" based network then the "Welcome Screen" is not an option for you to use...) because this gets you the ability to log on to ANY user account, whereas under the "Welcome Screen" you can NOT access hidden users.
If you wish to turn off the "Welcome Screen"
1) Start > Control Panel > User Accounts
2) Select "Change the way users log on or off"
3) Uncheck the "Welcome Screen" option
4) Click "Apply Options"
5) The settings will take effect when you log off.