Python and Printing

[Mix]

I have pictures (JPEG) which I get from a database and dump in an
arbitrary directory.
To print a picture I do the following:

      import os
      os.system("lpr lena.jpg")


My problem is that page orientation is always"landscape" instead
"portatrait".  What
switch is there to specify orientation for "lpr" if any?

P.S. I'm working under linux (redhat 7.0 distribution ).