How to insert topic pictures
 

I would like to insert topic pictures.

example, my forum site www.blackberryos.com/forums/

In front of all the Blackberry phone topics ie) Blackberry Storm, Bold, Curve, I want to insert a 50x50 image/icon for that topic. How do I go about doing that?

Also, is there any way to remove the forum contains new posts/ no new posts images from being visible?

Thanks in advanced.