I've search high and low for the answer to this one with no luck. I am trying to display a simple grid of child posts on the parent post's page and would like to use the default featured image feature of wordpress to display the $child_post images.
I assumed that I could just use
<?php echo $child_post->the_post_thumbnail(); ?> but it returned an error of PHP Fatal error: Call to undefined method stdClass::the_post_thumbnail()
Should I be doing this a different way?