3.6) The images.

type gr_bitmap =
  { bm_window : gr_window
  ; mutable bm_left : int
  ; mutable bm_top : int
  ; mutable bm_bitmap : image
  ; mutable bm_callback : gr_bitmap -> event -> bool
  }
;;
the variables needed to manage an image of type gr_bitmap are: The definitions linked to gr_bitmap are:
gr_icon_size : int
defines the standard size of an icon (32 pixels).
gr_draw_bitmap : gr_bitmap -> unit
gr_draw_bitmap Bitmap draws the image Bitmap.
gr_draw_center_bitmap : gr_bitmap -> rect -> unit
gr_draw_center_bitmap Bitmap Rect draws the image Bitmap in the center of the rectangle Rect.
gr_bitmap_managed : gr_bitmap -> event -> bool;;
its the function used by Camlwin to manage the images.