Text/image overlay in category and subcategory

Anyone know how to fix the issue with text overlaying the image in categoy/subcategory of default theme?
![22](https://cloud.githubusercontent.com/assets/8557382/4045243/2382b7f8-2d28-11e4-9523-338d0a96cbf7.png)

Thanks for any and all help :-)

A frustrated newbie..