> HTTrack is a great program, but recently I got a 
> problem which I can't solve.
> I want to spider trough I complete Website (all 
Pages) 
> but only save certain file types (*.png for 
example). 
> I can't figure out how to manage this with the 
filter 
> rules. Is it possible?
You'll have to download at least all files wanted AND 
html pages, because all links are located inside them.

A filter like:
-* +*.png +www.yoursite.com/*.html 
+www.yoursite.com/*.htm +www.yoursite.com/*/*[]

Should work. Ensure that you included all html pages: 
if you have asp or php pages on this site, add also:
+www.yoursite.com/*.php +www.yoursite.com/*.asp

and so on..