Blog Directory listing - how to style and can I add photos of products under each store

I have Marketpress set up and I would like to style the store listing which is being created by Blogs Directory. I would like to know where to change the CSS for general styling but also I wanted to know if I could add thumbnail photos of products sold by each store in that listing.

This is another website doing sort of what I want to do. http://madeit.com.au/Main/Stores

Thanks,
Nat.