Gallery with timthumb thumbnails

Hi,

this is the link to the webpage: link.

I use timthumb.php script to resize the featured images with each post. Now the problem is, the thumbnail only shows when hovering over each frame. But it should be visible at first sight….

Now in IE7 only 1 shows up…. *sigh*

This is my code:

<h2>Nieuwbouw</h2>

		<?php if (have_posts()) : ?>

					 <ul class="referentielijst">

                <?php

                $tmp = $wp_query;
                $wp_query = new WP_Query('cat=3&post_per_page=50');

                if(have_posts()) : while(have_posts()) : the_post(); ?>

                    <a href="<?php the_permalink(); ?>" title="<?php the_title(); ?>">

                        <?php

                            $image_id = get_post_thumbnail_id();

                            $image_url = wp_get_attachment_url($image_id);

                            ?>

                            <li class="image-teaser"><img src="<?php bloginfo('template_directory'); ?>/timthumb.php?src=<?php echo $image_url; ?>&w=150&h=120&q=100" alt="<?php the_title();?>" /><a href="<?php the_permalink() ?>"><span class="caption"><?php the_title(); ?></span></a></li>

				<?php endwhile;

                endif; ?>

      		</ul>

	<?php else : ?>

		<h2>Geen referenties gevonden.</h2>

	<?php endif; ?>