How to Change Windows XP Logon Screen background

You can put your favorite image or picture in the background of the logon screen by doing the following methods.

1. Click the Start button and select “Run”
2. In the “open” field, type regedit and click ok
3. In the registry editor, navigate to HKEY_USERS\.DEFAULT\CONTROL PANEL\DESKTOP and double-click the string “wallpaper”
4. Enter the full path and filename of the .bmp image that you want to use as background (the image must be in .bmp format)
5. Click “ok” and close the registry editor

Note: Should Restart the computer for changes.
If you want to see the background set in tiled effect with the bitmap then follow the below steps.

1. Click the Start button and select “Run”
2. In the “open” field, type regedit and click ok
3. change the string HKEY_USERS\.DEFAULT\CONTROL PANEL\DESKTOP\TILEWALLPAPER to “1″ instead of “0″
4. Click “ok” and close the registry editor