Windows 7 officially supports logon UI background customization
” Although this functionality was designed with OEMs in mind, it is pretty easy to turn on and off using regedit and some images lying around your hard drive. First, a check is made to determine if the customization functionality is enabled or not. More precisely, a DWORD value named OEMBackground in the HKLM\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\Background key Read more about Windows 7 officially supports logon UI background customization[…]