Images Appearing Tiny in Tables

I am working on fixing a WP site that was designed using the Responsive theme. It’s very basic but has lots of wonky problems. The big one right now is that when I got the rest of the site up to par, the images inside tables are now showing up as tiny thumbnails instead of full-size pictures. (Here: https://www.gaspgroup.org/about-us/board-of-directors/ and here: https://www.gaspgroup.org/about-us/staff/.)

I tried Googling to see if there was some bug with images in tables in the Responsive theme but came up with nothing. Anyone got any ideas?