Change Windows 7 Logon Background

Change Windows 7 Logon background wallpaper easily
Go to Run>type 'regedit' >Navigate to the following path:

 
HKLM/Software/Microsoft/Windows/CurrentVersion/AuthenticationLogonUIBackground

Search for the DWORD value type named 'OEMBackground' and change its value from 0 to 1 (default value is 0).

Navigate to the following folder:

%windir%system32oobeinfobackgrounds

Copy your wallpapers in this folder. This folder might not be there because the registry and this folder is for OEM versions of Windows 7 only. If not, you can create it yourself. Wallpapers should be in less than 256 KB in size with JPG format.
The following files (sorted by width-to-height ratio) are supported in this folder:

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-)


The backgroundDefault.jpg image is loaded and stretched-to-fit when a resolution/ratio-specific background cannot be found. The other resolution/ratio-specific files are self-explanatory. If the background cannot be loaded (e.g. image physically too large, incorrect ratio, etc.), the default SKU-based image is loaded from imagesres.dll.