I want the same effect as when you type Ctrl + F5 ( you 
force to download the page from the web server, and not 
from the proxy-cache installed by the operators). 
When I change a page of my site, but not the name of the 
page URL, I need to clean the proxy-caches between the web-
server and the browsers from the old page.
So, I think that httrack has some way to ask all the pages 
and add to the URL the character Crtl+F5, this would force 
the load of the page with the new images.
Thank Xavier, for your answer