> Try the following filter:
> -* +*.gif +*.jpg +*.png +*.css +*.js

This works well, (also works without -n "Follow 
external links")

PLEASE document this in the help file, as I had to 
search before getting this solution!

 although: I thought this is exactly what -n should do 
without -*.

I think -n fails because -r is evaluated first on html 
and non-html links and then excludes the non-html to 
be allowed by -n.

[refer forum thread id#675. phase1(-r) before phase3(-
n)]

(Observation: seems that httrack does not discriminate 
between an html page and an image file)