Calling an attached image

I’m already using this code to call thumbnails:

<?php
$args = array(
	'order'          => 'ASC',
	'post_type'      => 'attachment',
	'post_parent'    => $post->ID,
	'post_mime_type' => 'image',
	'post_status'    => null,
	'numberposts'    => -1,
);
$attachments = get_posts($args);
if ($attachments) {
	foreach ($attachments as $attachment) {
		echo apply_filters('the_title', $attachment->post_title);
		echo wp_get_attachment_link($attachment->ID, 'thumbnail', false, false);
	}
}
?>

When you click on a thumbnail, you get this larger image as a result:

This is the result I want, however, I don’t want that large image to be clickable.

The attachment.php code looks like this:

<?php $attachment_link = get_the_attachment_link($post->ID, true, array(515, 800)); // This also populates the iconsize for the next line ?>
<?php $_post = &get_post($post->ID); $classname = ($_post->iconsize[0] <= 128 ? 'small' : '') . 'attachment'; // This lets us style narrow icons specially ?>

          <?php echo $attachment_link; ?><br />
				<?php the_content('<p class="serif">Read the rest of this entry &raquo;</p>'); ?>

Obviously the code in attachment.php needs to change, but I don’t know what to change it to. Nothing seems to work.

We are in dire need of an update to the WordPress Attachment Codex.