> Is it possible to call httrack from a web page or CGI 
> script?  The objective is when a user visits MySite1, 
> httrack on MySite1 downloads an image file from MySite2 
> and displays it on the web page from MySite1.

Err, httrack is not the best solution IMHO for that 
(downloading a single file) -- scripting languages have 
generally built-in routines to fetch files from the WWW.

For example, in php, you can do:
$fp = fopen(http://www.whatever.com/..","rb);
fread($fp,..)