I have Windows 7. I thought it might be nice to change the look of the login screen to something a little more personal.
Microsoft was kind enough to allow that so that OEM's could put their company logos, etc. on the login screen.
To do this, simply follow these instructions
HKLM\Software\Microsoft
\Windows\CurrentVersion\Authentication\LogonUI\Background
3. Now in right-side pane, change value of OEMBackground to 1.
4. Now place your custom image in %windir%\system32\oobe
5. Create a new folder info and background within newly created info folder
Folder path should look like this %windir%\System32\oobe\info\backgrounds
6. Now place your desired logon wallpaper within this background folder with file name as backgroundDefault.jpg
Images Name with resolutions
backgroundDefault.jpg
background768×1280.jpg (0.6)
background900×1440.jpg (0.625)
background960×1280.jpg (0.75)
background1024×1280.jpg (0.8)
background1280×1024.jpg (1.25)
background1024×768.jpg (1.33-)
background1280×960.jpg (1.33-)
background1600×1200.jpg (1.33-)
background1440×900.jpg (1.6)
background1920×1200.jpg (1.6)
background1280×768.jpg (1.66-)
background1360×768.jpg (1.770833-)
Please NOTE: Images must be less than 256kb in size
The backgroundDefault.jpg image is loaded and stretched-to-fit when a resolution/ratio specific background cannot be found.