Using image_attachment_link after wordpress update

I’m using jQuery SlideViewerPro on this website to achieve a thumbnail gallery of wedding dress images. Using the following code, this worked fine until I recently updated from WP 2.8 to WP 3.3.

<div id="dress-gallery">
	<div id="mygalone" class="svwp" style="">
	    <ul style="">
		<?php
			$args = array( 'post_type' => 'attachment', 'numberposts' => -1, 'post_status' => null, 'order' => 'ASC', 'orderby' => 'title', 'post_parent' => $post->ID );
						$attachments = get_posts($args);
			if ($attachments) {
				foreach ( $attachments as $attachment ) {
					echo '<li>';
					the_attachment_link( $attachment->ID, $fullsize = true, $deprecated = false, $permalink = false );
					echo '</li>'.PHP_EOL;
				}
			}
		?>
	    </ul>
	</div>
</div>

Before, the images fit nicely as scaled down, medium size images (not thumbnails). But now, when I leave $fullsize = true on, the slider window pulls the image size from the actual image, which is intentionally large for use with the jqzoom to show details on hover (from a link to the full size). I’ve got this set to $fullsize = false so it isn’t broken in browser

Basically, does anyone know of any hickups in the update that could cause this issue? I spent a great deal of time getting this presentation to work and not it’s shot. Is my only hope downgrading?