Help with creating Video archive with get_pages

I’m using the following to list the pages and their children, but I need the image out of the loop (but I still need to display it), so I can style the actual page titles in an <ul> and it won’t affect the image. I attached an image to give you an idea of what I want. If there is a better way to do this besides get_pages? Thanks!!

Each Video is its own page as well.
https://i.stack.imgur.com/FmH6L.jpg

<?php
    $args = array(
    'child_of'     => 200,
    'title_li'     => '',
    'depth'			=> 0,
    'sort_order'	=> 'DESC',
    'sort_column'	=> 'post_date'
    );

    $pages = get_pages( $args );

    $output = "";

    foreach($pages as $value){
	    $thumb = get_the_post_thumbnail( $value->ID, full, $attr = '' );
	    $output .= $thumb;
	    $output .= "<li>";
	    $output .= "<a href='" . $value->post_name . "'>" .  $value->post_title . "</a>";
	    $output .= "</li>";
    } 

    echo $output;
    ?>