categories issues

Ok I’m pretty new to wordpress so forgive me as I’m sure there must be a simple solution to my issue.

I’ve been trying to set up product categories for an alcohol delivery service:

Drinks
with sub categories Vodka, Champagne etc
Snacks
with sub categories

When on the shop page an image appears for each of the categories – how to I remove this? And then again for the subcategories.

Please view the website as it will better explain my issue – http://www.justcalljohnnie.com/ibiza/?post_type=product

Thank you

http://wordpress.org/extend/plugins/woocommerce/