Fnd_Bttn_SetBackgroundPict

            Fnd_Bttn_SetBackgroundPict (left; middle; right)

              Parameter                   Type           Description
              left                        Picture        Left edge of the button
              middle                      Picture        Middle of the button (generally 1 pixel wide)
              right                       Picture        Right edge of the button

            If you would like to design your own artwork to be used as a button background, pass images to these
            button parts using this method.
              GET PICTURE FROM LIBRARY("MyButtonBackgroundLeft";$leftImage)
              GET PICTURE FROM LIBRARY("MyButtonBackgroundMiddle";$middleImage)
              GET PICTURE FROM LIBRARY("MyButtonBackgroundRight";$rightImage)
              Fnd_Bttn_SetBackgroundPict ($leftImage;$middleImage;$rightImage)

            For example these images are used to create the Small1 button for Macintosh (enlarged):

                 Left            Middle   Right

            All three images must be exactly the same height. The middle image must be exactly 1 pixel wide. It will
            be replicated as needed to provide a final button background image wide enough for the specified icon
            and text.
            The middle image is required, but the outer images (left and right) are optional. For example, the
            Macintosh style Large button uses only a middle image to create the button background. No left or right
            ends to the button are used.