Are you bored of this default Windows logon screen background?
If so, time for a change. And here is how you can do it.
First, open Regedit and navigate to the following key,
and set the DWord key OEMBackground to 1. If you don’t find the key there, create one.
Then, copy your desired background image in JPEG format to the following folder.
You can place a series of pictures there to fits the different size of resolution you may use. Or, you can just put one name it as backgroundDefault.jpg there. Windows will automatically stretch to fit the screen in logon screen. Note that the size of background image can’t be greater than 512k. Or it will fail to load, and will load the default boring one instead. See more details about the background images used in logon screen, check this post from Within Windows.
The change will take effect right after you log off.
The procedure of customizing this is quite tedious, I have to admit. And that’s why there are number of 3rd party tools out there making life a bit easier for you. Pulse is one of them that is open source and that can rotate the screen background periodically too. Windows 7 Logon Screen Tweaker is another one. And the Windows 7 Logon Background Changer. Any one of these should do the work for you.