Need Photos to Appear in Product Listing

I have my store set up – it works great, but in the listing of products (which I put on the main store page), I need to have a thumbnail of the image within the listing. I can’t find any way to do this. You can see what I’m speaking about at

https://www.gallagherpottery.com/store

The categories also don’t work for me at all – they boot me back to the home page, but I’ll tackle that in a separate question.

thanks.