Кликабельность картинки (не работает)

<div class="left">
<?php if ($thumb) { ?>
<div class="image"><a href="<?php echo $popup; ?>" title="<?php echo $heading_title; ?>" class="colorbox"><img src="<?php echo $thumb; ?>" title="<?php echo $heading_title; ?>" alt="<?php echo $heading_title; ?>" id="image" /><span class="image_zoom"></span></a></div>
<?php } ?>
<?php if ($images) { ?>
<div class="image-additional">
<?php foreach ($images as $image) { ?>
<a href="<?php echo $image['popup']; ?>" title="<?php echo $heading_title; ?>" class="colorbox"><img src="<?php echo $image['thumb']; ?>" title="<?php echo $heading_title; ?>" alt="<?php echo $heading_title; ?>" /></a>
<?php } ?>
</div>
<?php } ?>
</div> <!-- left -->