Unabe to display featured images (as Thumbnails) on blog posts page.

Hello guys,

I am using the ZEAL template.

For my 'blog' page where my posts show up, I am unable to display the Featured image as a thumbnail. When I chose the 'default' post type the Title of the post appear as well as the excerpt but the featured image is not showing up. How can I make it show up?

See https://nedelchevcars.siterubix.com/projects/ The Blue Sprint post for example.

Thank you in advance!

Asen