Displaying Images on /Store

We are migrating an existing client's store over, and they'd like to display images on /Store, either general category images or actual product images. They would like a grid look, but we can't change the theme to use gridmarket - the site is running studio.

I'd hoped there would be an easy way to style the store pages using shortcodes but if there is I'm not seeing it. Has anyone done a css grid that will work with studio? That /store page is one ugly beast:

http://www.stoptheroundabout.com/store/

Thanks in advance!