Adding a Featured Image Thumbnail after Blog Post Title on Blog Feed Page

Hello all!

I want to know how I can add the featured image that I have set for my blog post to show up on my blog page feed.

The theme currently doesn't support it but I'd like to know what code I can enter in the html or CSS so that it shows up underneath the Blog Post Title in the Blog Posts Page and before the post summary/read more button.

http://www.theta.geofflawtononline.com/blog/

Thanks!