Muestra categorías con thumbnail en la portada de Wordpress

<?php
/**
 * @package WordPress
 * @subpackage Default_Theme
 */

get_header();
?>
	<!-- content -->
	<div id="content" class="narrowcolumn">

		<h1 class="main_title">Ultimos Videos</h1>
<!-- END OF TAG -->
		<?php if (have_posts()) : ?>
		<div id="videos">
		<?php $i=0; while (have_posts()) : the_post(); $i++; ?>
			<!-- post -->
			<div class="video<?php if($i%4==0) : ?> video_last<?php endif; ?>" id="video-<?php the_ID(); ?>">
				<h2><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title_attribute(); ?>"><?php echo thman_get_limited_string($post->post_title,17); ?></a></h2>
				<div class="thumb">
				<a href="<?php the_permalink() ?>" title="<?php the_title_attribute(); ?>"><?php $thumb = thman_getcustomfield('thumb',get_the_ID()); if(!empty($thumb)) : ?>
					<img src="<?php echo $thumb; ?>" alt="<?php the_title_attribute(); ?>" />
				<?php else : ?>
					<img src="<?php bloginfo('template_url'); ?>/images/pic_empty.gif" alt="<?php the_title_attribute(); ?>" />
				<?php endif; ?></a>
				</div>
				<div class="info">
					<div class="info_left">
						<p class="duration"><?php $duration = thman_getcustomfield('duration',get_the_ID()); if(empty($duration)) $duration = 'Online'; echo $duration; ?></p>
						<?php if(function_exists('the_views')) {  ?><p class="views"><?php the_views(); ?></p><?php } ?>
					</div>
					<div class="info_right">
						<?php if(function_exists('the_ratings')) { ?><div class="rating"><?php the_ratings(); ?></div><?php } ?>  
					</div>
				</div>
			</div>
			<?php if($i%4==0) : ?><div class="clear"></div><?php endif; ?>
			<!-- /post -->
		<?php endwhile; ?>
		</div>
		<?php 
		$next_page = get_next_posts_link('Previous'); 
		$prev_pages = get_previous_posts_link('Next');
		if(!empty($next_page) || !empty($prev_pages)) :
		?>
		<!-- navigation -->
		<div class="navigation">
			<?php if(!function_exists('wp_pagenavi')) : ?>
            <div class="alignleft"><?php echo $next_page; ?></div>
			<div class="alignright"><?php echo $prev_pages; ?></div>
            <?php else : wp_pagenavi(); endif; ?>
		</div>
		<!-- /navigation -->
		<?php endif; ?>
		
	<?php 
	
	else :

		?><p class="nopost">Sorry, but you are looking for something that isn't here.</p><?php

	endif;
?>

	</div>
	<!-- /content -->

<?php get_sidebar(); ?>

<?php get_footer(); ?>