generally, to show captions under the featured image in the single post, try to add this code to functions.php of your (child) theme:
// dec 17 2016 @alchymyth
// filter for single post, in the loop, to show caption, if available, on thumbnail, wrapped with '.wp-caption thumb-caption' div;
// show just the thumbnail otherwise
add_filter( 'post_thumbnail_html', 'add_post_thumbnail_caption',10,5 );
function add_post_thumbnail_caption($html, $post_id, $post_thumbnail_id, $size, $attr) {
if( $html == '' || !is_single() || !in_the_loop() ) { //do this only for single post in the loop//
return $html;
} else {
$out = '';
$thumbnail_image = get_posts(array('p' => $post_thumbnail_id, 'post_type' => 'attachment'));
if ($thumbnail_image && isset($thumbnail_image[0])) {
$image = wp_get_attachment_image_src($post_thumbnail_id, $size);
if($thumbnail_image[0]->post_excerpt)
$out .= '<div class="wp-caption thumb-caption">';
$out .= $html;
if($thumbnail_image[0]->post_excerpt)
$out .= '<p class="wp-caption-text thumb-caption-text">'.$thumbnail_image[0]->post_excerpt.'</p></div>';
}
return $out;
}
}
might need to be adapted to work with your commercial theme.
