The code will be added to wp-content/themes/kleo-child/functions.php
COPY CODE
add_action( 'kleo_before_main', 'sq7rdu_show_featured_before_content' );
function sq7rdu_show_featured_before_content() {
	if ( is_single() && has_post_thumbnail() ) {
		echo '<div class="fullwidth-image-before-content">';
		the_post_thumbnail( 'full' );
		echo '</div>';
	}
}
Below is a screenshot with an example of the function usage.

 
  