'General
Declare Function SystemParametersInfo Lib "user32" Alias "SystemParametersInfoA" (ByVal uAction As Long, ByVal uParam As Long, ByVal lpvParam As Any, ByVal fuWinIni As Long) As Long
Public Const SPI_SETDESKWALLPAPER = 20

'Place the following code in under a command button or in a menu, etc...

Dim ChangeWP
dim source
source = "C:\windows\setup.bmp"
ChangeWP = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, source, 0)