Is there a module/component/mambot for joomla that will allow you
to assign a thumbnail that will be displayed in section lists (for categories) and category
lists (for content items)

I have a section called fish and categories under that section for the families of fish for example tangs.  When you go to the fish section and the list of categories comes up I when a thumbnail of a tang to be displayed next to the name in the list.  Further when you click on the category tangs  a list of the specific types of tangs comes up and I want a picture of the each tang to be displayed next to the name.

Is there something that is already written to do this, or will I have to hack the content component?