In this section:
%wp (Wallpaper bitmap) takes the name of a bitmap resource. bitmap is a standard character string. %wp "wallpapers" the window with the bitmap before the text and controls are drawn.
i=winio@('%bg[grey]%fn[Times New Roman]&')
where the resource script chitz.rc contains:
chitz BITMAP c:\windows\chitz.bmp
%wp (Wallpaper bitmap) is most effective in windows that contain only graphical objects. If the bitmap is smaller than the dimensions of the window, it will be repeated horizontally and vertically to fill the space. Therefore, your bitmap should either be sufficiently large, or it should contain a pattern that is designed to repeat, like the standard Windows wallpaper bitmaps. A grave accent (`) is added to %wp in order to ensure that the window will be expanded to hold at least one copy of the bitmap.