Bitmap-Number
This property identifies the image to be displayed when the Check-Box control is in normal status. The number corresponds to the position occupied by the image in the bitmap strip.
 
Example - Define a checkbox in screen section and define which bitmap to use when unselected from an image containing many bitmaps
screen section.
...
03 screen-1-cb-2 Check-Box
   line 27.0
   column 10.0
   size 116
   lines 31
   id 11
   flat
   title "E-mail results?"
   bitmap-handle my-cb-png
   bitmap-number 1
   bitmap-width 20
   title-position 2
   bitmap-selected 2
   .