<?php
$imgargs = array('post_type' => 'attachment','post_mime_type' => 'image','numberposts' => -1,'order' => 'ASC','post_status' => null,'post_parent' => $post->ID );
$attachments = get_posts($imgargs);
if ($attachments) {
	foreach ($attachments as $attachment) { $img = wp_get_attachment_thumb_url( $attachment->ID );
	break; }
} ?>
<img src="<? echo $img ?>" alt="" />