Well, I see from the error logs that httrack was obeying the robots.txt
exclusion rule on the website. Once I set it to ignore, it started downloading
the site cgi links.

Each CGI page has a 640x480 fractal image named 0.jpg.  For some reason,
httrack fetches all the icon.jpg files, but none of the 0.jpg files, which are
the images I'm trying to capture.

I set the rule +*.jpg and -*.mpg because I don't want the mpeg animations,
just the jpegs.