The screensaver and Desktop (along with other appearance settings) that are visible before any user has logged on are controlled by the Registry settings. You can use the Registry editor to make the display settings at log-on match to those of the current user. First, set the screensaver and Desktop image the way you want them to be at log-on. Next, click on the Start button and select Run. Type in 'regedit' and press Enter. Look for the following key:
Click on Desktop in the left pane to highlight it then select 'Export' from the File menu. Name the file 'FixDefault' and save it to the Desktop. Now open the FixDefault.reg file in Notepad and replace all instances of 'HKEY_CURRENT_USER\' to 'HKEY_USERS\.Default\' then save the changes. Finally, double-click on the 'FixDefault.reg' file and select Yes to transfer the new settings.