bitmap (blank image) plot rendering without X11

Hi,
I am trying to generate plots on our unix (no X) server to be included 
in our web-pages -> specifically pngs.

Without X, png() obviously doesn't work, so I have been trying to define 
the graphics print device bitmap as described in the help:

 > bitmap(file="plot.png", type = "png256", height = 6, width=6,res=72)
 > pie(c(12,5))
 > dev2bitmap(file="plot.png", type = "png256", height = 6, width = 
6,res=72)

I end up with "plot.png" as a nonzero png file, but it is always 
blank... I have gs 6.51 installed & R_GSCMD=/usr/bin/gs set.

generating Rplot.ps; pstoimg -antialias (or pstopnm)  would also be an 
acceptable solution if I knew how to control the size of the generated 
image, or if the ps generated by R was consistently compatible with 
pstopnm.  (ps2ps causes me to lose parts of the image)..

So I am asking know-alls of R... if they know of a solution?  We are 
generating thousands of images, so work on a windows or slower machine 
with X is not really an option...


any help much appreciated!
Beracah

Beracah Yankama
Director, StudentsReview
StudentsReview.com
beracah at studentsreview.com