Picture and Bitmap unified?

[Zuurbier, E. - AMSXE]

I thought it would be a nice idea to be able to make my own bitmaps.
Of course I could do that by diving into the file-format of bitmaps and
write functions to fill them. But would not it be nice if the existing
Picture drawing functions would also be available for Bitmaps?

In that case for instance the following function types could change from

DrawPoint   ::  !Point  !Picture -> Picture
DrawLine    ::  !Line   !Picture -> Picture
DrawCurve   ::  !Curve  !Picture -> Picture
(etc)
 
to

DrawPoint   ::  !Point  !p -> p | Pict p 
DrawLine    ::  !Line   !p -> p | Pict p
DrawCurve   ::  !Curve  !p -> p | Pict p
(etc)

or there could be a

class Pict p
where   DrawPoint   ::  !Point  !p -> p
        DrawLine    ::  !Line   !p -> p
        DrawCurve   ::  !Curve  !p -> p
        (etc)

with instances for Picture and Bitmap