<div class="thumbnail-img">
<?php
$lastBlog = new WP_Query('post_type=post&posts_per_page=2');
if ($lastBlog->have_posts()) {
while($lastBlog->have_posts()) {
$lastBlog->the_post();
if(has_post_thumbnail()){
the_post_thumbnail();
}
}
}
?>
</div>
-> Try Like This