looked horrible

When I installed this all the images jumbled together. I also didn’t realize it was based on comment count. You can make almost no modifications to this widget including image size. It didn’t work for me.

As you can see in the plugin’s description page, I have mentioned that “This plugin uses custom thumbnails, you can use Regenerate Thumbnails to regenerate the thumbnails for your image attachments.”
Also, I tried to make the plugin as simple as possible, for that reason there is no option to make changes to the photos. However, the plugin is fully responsive and once you regenerate the thumbnails it should work fine with your current theme.