function ac_get_post_thumbnail_id($post) { $post = get_post($post); $post_type = get_post_type($post); switch ($post_type) { case 'attachment': // Post ID is the attachment ID for images return $post->ID; case 'ac_gallery': return ac_gallery_get_cover_image_id_for_gallery($post); default: return get_post_thumbnail_id($post->ID); } }
function ac_gallery_get_cover_image_for_gallery($gallery_id, $image_size) { $image_id = ac_gallery_get_cover_image_id_for_gallery($gallery_id); if ($image_id) { // Return the first instance $img = wp_get_attachment_image_src($image_id, $image_size, false); $img = $img[0]; return $img; } return false; }