This function take a "Picture" object and draw it
in the current plot region.
picture(picture, xleft, ybottom, xright, ytop, ...)
A "Picture" object.
The location for the left edge of the picture.
The location for the bottom edge of the picture.
The location for the right edge of the picture.
The location for the top edge of the picture.
graphical parameters.
Paul Murrell
The positions supplied, i.e., xleft, ..., are relative to the
current plotting region. If the x-axis goes from 100 to 200 then
xleft should be larger than 100 and xright should be
less than 200.
readPicture and
grid.picture