Wordpress recent posts with thumb check

recent posts.php

<ul>
 
<?php $the_query = new WP_Query( 'posts_per_page=2' ); ?>
<?php while ($the_query -> have_posts()) : $the_query -> the_post(); ?>
    <li class="col-md-6"><a href="<?php the_permalink() ?>"><?php the_title(); ?></a>
    <?php
    if ( has_post_thumbnail() ) {
        the_post_thumbnail();
    }
    else {
        echo '<img src="' . get_bloginfo( 'stylesheet_directory' ) 
            . '/images/thumbnail-default.jpg" />';
    }
    ?>

   <?php the_excerpt(__('(Ler mais..)')); ?>
</li>

<?php
    endwhile;
    wp_reset_postdata();
?>
</ul>