Logon Controller is a system enhancement tool for Windows 7. It allows you to change the logon screen of your operating system. By default, you are shown the Windows Wallpapers that come bundled with Windows 7 and you can choose from any of those to set your logon screen. Additionally, you can browse for pictures on your computer and set those, too. However, you can't really decide how the picture is going to be shown if it is not the correct size. Thus, you are better off sticking to wallpaper-size images.
I like the fact that Logon Controller takes control of the operating system and allows you to do 1-click swapping of logon screens. That is all it takes: you click the image, and it gets locked on your logon screen. For those who would rather have something plain as a log-on screen, Logon Controller also allows to use solid colors as backgrounds. There is also a feature that locks the computer, so that you can "preview" the logon screens that you set using the application. That is really a nice addition. Make sure you remember your password though.