I have a service that makes a background image comprised of different information (Name, IP, MAC, etc).
My intention is to have the service change the HKEY_USERS\.DEFAULT\Control Panel\Desktop\Wallpaper key before winlogon accesses it when displaying the login screen (Not welcome screen). But it doesn't seem to do it fast enough. If I reboot again the wallpaper will show, but it will be one reboot behind if you get my drift.
SystemParametersInfo() with SPI_SETDESKWALLPAPER doesn't seem to work either.