Windows 7 has got built-in feature to change Windows 7 Logon background and we have already covered Logon Changer & LogonUI background changer for Windows 7. For Windows Vista & XP Logonstudio & XP LogonUI Changer are best tool to use.
Here is yet another similar free too Windows 7 Logon Controller to Configure/Change Windows 7 Logon Background Wallpaper. Logon Controller lets you to set any jpeg image file as logon background, lock computer, reset to default background.
Windows 7 Logon Controller
Download Logon Controller for Windows 7 to Change Windows 7 Logon Screen.