Incantation Pro: Remove Thumbnails from blog posts list

I am working with the Incantation Pro theme.

I want to remove the thumbnail image from the blog posts on the main blog page. These thumbnails appear both on the main page – blog list of all posts and on the single post page.

I want to keep the banner image but remove the thumbnail below that on both the main posts page and from the single posts page.

Here is a link to the blog I am working on: