How to link teaser taxonomy image to node page?

I'm trying to get my teaser image to link to the full node page. Does anybody have an idea how I can override the url of the teaser image?
At the same time I would like to set different sizes for both teaser and full node view.

I tried using the link to full sized image documentation: http://drupal.org/node/228645
But don't really know where to make the changes. Can anyone help me out on this one. Maybe it can also make the future features list.

Awaiting your wisdom peoples...