> However, the offline browsing is extremely slow.  I 
> check the source, there are scripts including banner 
> ads, popup windows and a webtrend live tracking ...  

Yes, filters like +*.gif means 'include ALL gif 
files', even banner ads - you may want to use instead 
something like:
+www.yoursite.com/*.gif
+www.yoursite.com/*.jpg
+www.yoursite.com/*.js

Again, '*' means 'any string'