Windows 7 Logon Background Changer is a free open source software that let you change the wallpaper of the Windows 7 logon screen (also known as "welcome screen", "login screen" or LogonUI).

Click the icon  to download.

It has been tested successfully with the final version of Windows 7 (RTM) and Windows 7 RC 7100. It works with Windows 7 Home Basic, Home Premium, Professional, Ultimate and Enterprise, in x86 or x64 (32 or 64 bits). It does NOT work with Windows 7 Starter (edition sold with most netbooks). It works also on Windows Server 2008 R2 (but you are not supposed to customize a server).