query_posts('showposts=5');
gibi bir ekleme yapın while döngüsünden önce.
kod böyle
<p><?php $postslist = get_posts('showposts=3'); foreach ($postslist as $post) : setup_postdata($post); ?>
<a title="<?php the_title(); ?>" href="<?php the_permalink(); ?>">
<?php $values = get_post_custom_values("resim"); ?>
<?php if($values==""){?><?php }else{ ?>
<img class="syresim" src="<?php echo $values[0]; ?>" alt="<?php the_title(); ?>" /><?php } ?>
</a>
<?php endforeach; ?>