Image not displaying

This plugin is working fine except it isn’t showing my image.

The image is the first item in the post page and not stored as a Featured Image. Is there any way to display it?

This is my shortcode

`[display-posts include_excerpt=”true” image_size=”thumbnail” wrapper=”div” tag=”volume-11″ posts_per_page=”12″]

https://wordpress.org/plugins/display-posts-shortcode/