$post_thumbnail_id = get_post_thumbnail_id( $post_id );
$size = apply_filters( 'post_thumbnail_size', $size );
if ( $post_thumbnail_id ) {
$post_thumbnail_id = get_post_thumbnail_id( $post_id );
$size = apply_filters( 'post_thumbnail_size', $size );
if ( $post_thumbnail_id ) {