Sub Category Preview Photo Is Blurry

How can I get a clear Preview Image for a Sub-Category? It's appearing blurry. 

It's fine when I upload it. When previewed on the site it's blurry.

In the listing layout (Design -> Page Display & Content Listing Layouts) the Size photo to use was set to mini for the on photo layout it is using. I changed it to small, which it should be, and looks better now. 

Looks great now. Could I have the Sub-Category centered on the page? It is currently left justified. 

You would need to change the category listing layout to thumbnail. 

Edit the parent category and click Layouts -> Category Layouts  and change it to thumbnail.