Question

Solution

You will use the SystemParametersInfo function found in the Windows API to set the desktop wallpaper. Drop a button on your form and in the OnClick event for the button place the following code:

procedure TForm1.Button1Click(Sender: TObject);
var
  PicPath: String;
begin
  PicPath := 'C:\WINNT\Prairie Wind.bmp';
  SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, pChar(PicPath), SPIF_SENDCHANGE)
end;