[R] jpeg in batch mode

[Elizabeth Purdom]

Hello,

I am running some commands in batch on a server that I SSH into; some of 
the commands call jpeg(). If I continue to stay signed on (with my 
xwindows working on my machine) then the jpeg() command works (with a 
single caveat, below). If I leave it and sign off (with a nohup command 
in front of my BATCH) then jpeg gives me an error like this:
  Error in X11(paste("jpeg::", quality, ":", filename, sep = ""), width,  :
         unable to start device JPEG
In addition: Warning message:
could not open JPEG file xyz.jpeg

I don't have this problem with pdf(); but the images I want to draw are 
really massive in terms of the number of points/images so they take 
forever to open in adobe (as well as being HUGE) so I'd like them in 
jpeg. Can I get around this somehow? I saw other people posted similar 
problems, but saw no solutions.

R-2.6.0, GNU/Linux

Thanks,
Elizabeth

My caveat from above about the jpeg working as long as I'm signed on: 
one time I got the mysterious error:
 > 
jpeg("~/batch5Effect/ProbPbsets_summaryHeatmaps%03d.jpeg",height=1200,width=800)
Error in jpeg("~/batch5Effect/ProbPbsets_summaryHeatmaps%03d.jpeg", 
height = 1200,  :
   X11 fatal IO error: please save work and shut down R

Even though it had just correctly done this same basic command a few 
lines back. I redid it (without changing anything that I was aware of) 
and it worked fine. So I don't think it's related.