If you put the code inside the_loop it will output the entire page, but if you put this code outside the loop, this is most likely after / below the last <?php endif; ?> this will create only a list of subpages with thumbnail.
on my customers page i did it like this:
<?php endwhile; else : ?>
<?php endif; ?>
<ul class="subpages">
<span style="display:none;"><?php the_ID(); ?></span>
<?php $parent = $post->ID; ?>
<?php
query_posts('posts_per_page=15&post_type=page&post_parent='.$parent);
while (have_posts()) : the_post();
?>
<?php $image_thumb = get_post_meta($post->ID, 'image-thumb', true); ?>
<li><?php the_post_thumbnail('single-blog-thumbnail'); ?>
<h4><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h4></li>
<?php endwhile; ?>
</ul>
I hope this is understandable…
