Few days back Windows7 Build 7057 leaked over the web. You can download it off torrents. New wallpapers and user images are added in this build. If you are still using XP or Vista and would like to try out these wallpapers and user images, you can do so as they are available for download separately. There are a total of 30 new wallpapers and 36 new user images for your start menu and your login screen.
Installing user images on Windows XP
To install them on XP, copy them to: C:\Documents and Settings\All Users\Application Data\Microsoft\User Account Pictures\Default Pictures
Installing user images on Windows Vista
To install them on Vista, copy them to: C:\ProgramData\Microsoft\User Account Pictures\Default Pictures