Query Thumbnails?

Currently I am display specific posts on a certain page like this:

<?php
$post_id=794;
$queried_post = get_post($post_id);
$title = $queried_post->post_title;
?>

How do i make it query the featured images as well?

I tried

<span>
<?php
$post_id=792;
$queried_post = get_post($post_id);
$title = $queried_post->post_content;
$post_thumbnail_id = get_post_thumbnail_id( $post_id );
$thumb = $post_thumbnail_id->post_thumbnail;?>
<?php echo $queried_post->post_content; ?></span>
<li><?php echo $thumb; ?></li>

But that definitely doesn’t work.

<?php the_post_thumbnail();?>

That doesn’t work as well as I am querying specific posts and it has to tie into my first call. Any help?