Cómo agregar post relacionados en PHP sin plugins

<?php
	$backup = $post;
	$tags = wp_get_post_tags($post->ID);
		if ($tags) {
		$tag_ids = array();
	foreach($tags as $individual_tag) $tag_ids[] = $individual_tag->term_id;
 
	$args=array(
		'tag__in' => $tag_ids,
		'post__not_in' => array($post->ID),
		'showposts'=>5, // Number of related posts that will be shown.
		'caller_get_posts'=>1
	);
 
	$my_query = new wp_query($args);
		if( $my_query->have_posts() ) {
		echo '<h3>Related Posts</h3><ul>';
			while ($my_query->have_posts()) {
		$my_query->the_post();
?>
 
		<li><a href="<?php the_permalink() ?>" rel="bookmark" title="<?php the_title_attribute(); ?>"><img src="<?php echo get_post_meta($post->ID, 'Image',true) ?>" width="149" height="96" alt="<?php the_title_attribute(); ?>" /></a><?php the_title(); ?></li>
 
<?php
	}
		echo '</ul>';
		}
	}
		$post = $backup;
		wp_reset_query();
?>

<div id="relacionados">
    <div class="relacionado">
        código de relacionado
    </div>
</div>

#relacionados .relacionado {
    float:left;
}