Purpose of jpeg2ps
==================
jpeg2ps converts JPEG files to PostScript Level 2 or 3 EPS. In fact, jpeg2ps
is not really a converter but a "wrapper": it reads the image parameters
(width, height, number of color components) in a JPEG file, writes the
according EPS header and then copies the compressed JPEG data to the output
file. Decompression is done by the PostScript interpreter (only PostScript
Level 2 and 3 interpreters support JPEG compression and decompression).
If you have a slow communication channel and a fast printer, sending
compressed image data is a big win.

WWW: http://www.pdflib.com/products/more/jpeg2ps.html