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 corresponding 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.
Note: if you are interested in conversion of JPEG or other formats to
PDF take a look at PDFlib (http://www.pdflib.com).