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).
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).
On a side note, this small program is WPF based, it's a nice technical demo of Windows Presentation Foundation capabilities for those interested in WPF. It requires a decent GPU for the 3D animations to run smoothly. It runs fine with my Radeon HD 3200 on my laptop computer, but it should also work with lower end graphic cards, albeit slowly.
What does it do?
It does NOT change any system file, and the program itself does not requires admin rights to run : it will just ask you to run as admin a very simple cmd file that creates the required folder and registry key with the appropriate rights. Any user of the computer will then be able to change the Windows 7 logon screen wallpaper. You can also prevent users from being able to change the logon screen wallpaper if you don't want them to be able to modify it without administrator rights (option available by clicking on the "Settings" button).
It creates a few JPEG files based on the image you want to put as wallpaper for the Windows 7 login screen, applies the appropriate cropping and sizing and saves them using the best compression quality possible.
点击右上角“Choose a folder”，选择壁纸所在的文件夹，然后在上面一排图片中选择你需要的图片，最后按“Apply”然后等待1-2秒就完成了壁纸的转换。
安全检测软件：ESET Smart Security (NOD 32)