Insert thumbnail feature to .php

Trying to add Recent Posts to my .php files.

I got it to display Heading and Except but can’t get thumbnail to display. Could someone assist, would like to get a thumbnail 100×100 in size – preferably aligned right.

<?php $the_query = new WP_Query( ‘posts_per_page=4’ ); ?>

<?php while ($the_query -> have_posts()) : $the_query -> the_post(); ?>

<h3>“><?php the_title(); ?></h3>

<?php the_excerpt(__(‘(more…)’)); ?>

<?php
endwhile;
wp_reset_postdata();
?>

Thanks in advance.

https://ww.wp.xz.cn/plugins/recent-posts-widget-with-thumbnails/