FrameMarket: Auto fetch featured image

Hi

My posts are not fetching featured image....I have published pages using "blognews template" what could be the problem?

Found this snippet...can I use it in my child theme's function.php code....will it help in anyway

function autoset_featured() {
global $post;
$already_has_thumb = has_post_thumbnail($post->ID);
if (!$already_has_thumb) {
$attached_image = get_children( "post_parent=$post->ID&post_type=attachment&post_mime_type=image&numberposts=1" );
if ($attached_image) {
foreach ($attached_image as $attachment_id => $attachment) {
set_post_thumbnail($post->ID, $attachment_id);
}
}
}
} //end function
add_action('the_post', 'autoset_featured');
add_action('save_post', 'autoset_featured');
add_action('draft_to_publish', 'autoset_featured');
add_action('new_to_publish', 'autoset_featured');
add_action('pending_to_publish', 'autoset_featured');
add_action('future_to_publish', 'autoset_featured');