Need Category Page to Display Posts Like A Gallery

I have seen a couple of threads where people were asking for something like this but the answers either seemed vague or non-existent.

I am trying to figure out how to have my category pages only show the thumbnail like a picture gallery. I cannot for the life of me figure out how to go about it in atahualpa. i would love it if I could get it to display a 3 column grid. Any thoughts?


Here is my site as is: http://www.fishshackdesign.com/categ...lank-pictures/

Thanks!

-HH-