<ul class="relatived-products">
<?php
$i=1;
foreach(get_the_category() as $category){
$cat = $category->cat_ID;
}
query_posts('cat=' . $cat . '&orderby=rand&showposts=5');
while (have_posts()) : the_post();
//$output = preg_match('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches);
//$imgnum = count($matches);
$thumb_f = wp_get_attachment_image_src( get_post_thumbnail_id($post->ID), 'full' ); $url_f = $thumb_f['0'];
?>
<?php if ($i % 5 == 0) : ?>
<li style="margin-right:0;">
<?php if ( $url_f ) { ?>
<a class="same_cat_posts_img" href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><?php echo '<img alt="'. the_title() .'" src="'.get_bloginfo('template_url').'/timthumb.php?src='.$url_f.'&w=100&h=100&zc=1" />';?>
<?php the_title(); ?>
</a>
<?php } else { ?>
<a class="same_cat_posts_img" href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><img alt="<?php the_title(); ?>" src="<?php bloginfo('template_url'); ?>/timthumb.php?src=/images/default-100.png&w=100&h=100&zc=1" />
<?php the_title(); ?>
</a>
<?php } ?>
</li>
<?php $i ++; else : ?>
<li>
<?php if ( $url_f ) { ?>
<a class="same_cat_posts_img" href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><?php echo '<img src="'.get_bloginfo('template_url').'/timthumb.php?src='.$url_f.'&w=100&h=100&zc=1" />';?>
<?php the_title(); ?>
</a>
<?php } else { ?>
<a class="same_cat_posts_img" href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><img alt="<?php the_title(); ?>" src="<?php bloginfo('template_url'); ?>/timthumb.php?src=/images/default-100.png&w=100&h=100&zc=1" />
<?php the_title(); ?>
</a>
<?php } ?>
</li>
<?php $i ++; endif; ?>
<?php endwhile; wp_reset_query(); ?>
<div class="clear"></div>
</ul>