MRO: Process commands like \psfig and \includegraphics directly, i.e. parse 
them, run pstoimg on the postscript file and add the image to an images list.
This requires:
- (maybe) a new array with image filenames and secifications, or can we
  use the same one as for the images coming out of dvips?
- recognition of certain directives, mainly the image size (i.e. width
  or height) and calculation of a corresponding pixel size
- in the long run support of rotation angles; these could be implemented
  in pstoimg with appropriate postscript code (like dvips does)

MRO: Add support of the <EMBED> tag when $NETSCAPE_HTML is set, so that this
stupid browser can deal with inlined PNGs correctly.

