<?php
$attachments = get_children( array('post_parent' => get_the_ID(), 'post_type' => 'attachment', 'post_mime_type' => 'image') );
foreach ( $attachments as $attachment_id => $attachment ) {
echo '<ol class="related-posts">';
echo ' ' . wp_get_attachment_link( $attachment_id ) . '';
echo '</ol>';
} ?>