If you select Now the logon screen will change now. You will need to select an option under Change, you can either change the logon screen for Every Logon or Every Day. Now, simply add your images to it, click choose button and browse to add the image, once you have added your desired images then you will need to do a little configuration regarding how these images should be displayed instead of the default logon screen.
Once you have installed the application, you will be able to select up to 10 images which you would like to use as your logon screen backgrounds and then those images are rotated each time you logon giving a cooler look to your Window 7. Now, there is no need to play with the registry settings, you can easily change the logon screen of your Windows in a couple of clicks only. Microsoft’s Windows Vista and XP have no support for changing the default logon screen, but in Windows 7 you can use the Logon Screen Rotator tool to rotate the logon screen during every logon.