get_users and User Photo

I am listing all my website’s users together by role (authors, contributors, subscribers, etc) in a custom directory page (NOT the author.php page). How can I pull each user’s thumbnail image to add to the listing?

Here’s the code I have, which works fine:

<?php

$args = array(
	'role' => 'author',
     'orderby' => 'display_name',
 'order' => 'ASC'

);

    $users = get_users( $args );
echo '<ul>';
     foreach( $users as $user )
     {
echo '<li>';
echo $user->display_name;
 echo '</li>';
     }
     echo '</ul>';
?>

Any help as to how to add the thumbnail to the listing?

Much appreciated!

https://www.ads-software.com/plugins/user-photo/