// thumbnail
function bm_extract_string($start, $end, $original) {
$original = stristr($original, $start);		<?php while (have_posts()) : the_post(); ?>
$trimmed = stristr($original, $end);
return substr($original, strlen($start), -strlen($trimmed));
}

burasi asagidaki sekilde olacak

     
// thumbnail
function bm_extract_string($start, $end, $original) {
$original = stristr($original, $start);
$trimmed = stristr($original, $end);
return substr($original, strlen($start), -strlen($trimmed));
}

<?php while (have_posts()) : the_post(); ?>

bunu kaldir ordan yanlislikla paste yapmissin sanirim.