That’s it. Worked perfectly. Here’s what I ended up with:
<?php
//get current page ID
$the_id = get_the_ID();
$args = array(
'child_of' => $the_id,
'title_li' => '',
'depth' => 0,
'sort_order' => 'DESC',
'sort_column' => 'menu_order'
);
$pages = get_pages( $args );
$output = '';
foreach($pages as $value){
$thumb = get_the_post_thumbnail( $value->ID, array(100,100), $attr = '' );
$output .= "<li>";
$output .= "<a href='" . $value->post_name . "' >" . $thumb . "</a><br />";
$output .= "<a href='" . $value->post_name . "' >" . $value->post_title . "</a>";
$output .= "</li>";
}
echo $output;
?>