> Well, .ico is not a well-known (by httrack) extension

I assume you meant to say .cur, but I get your point. And 
I'll try your suggestion.

Ok, but even if I add +*.cur to the scan rules it doesn't 
help. So can I ask, does HTTrack scan for the tag "url
('....')" in style sheets, such as is used for background 
images or custom bullet points?