Categories pages images

Hi, Can you please advise, How can I make the product categories display in smaller boxes and next to each other (4 in a row)? I know how to do this on an ordinary page but the category pages are not editable with the visual editor.

I don't like how they are just below each other.. It's not easy to navigate when there are 16 categories to show. Only the image place holders are showing at the moment but I will add the images later. I have noticed that it does not matter what image size I use, the boxes always stretches out to the same size. Here is a link to one of the categories pages

http://www.absolutecateringequipment.co.uk/product-category/food-storage/