WordPress Loop - skip posts without a thumbnail - wordpress

Question

I want skip every post that has no thumbnail. The code does not work properly yet.
Actually the script doesn't show posts without a thumbnail - that's good, but in the loop the post with no thumbnail is still counted as a post.
So when i have for example 10 posts in my wordpress database. I want show 5 of them. But only the posts who has a thumbnail.
<ul>
<?php
$args = array( 'numberposts' => 5,
'orderby' => 'date',
'order' => 'DESC',
'post_type' => 'post',
'post_status' => 'publish'
);
$my_posts = get_posts( $args );
global $post;
foreach( $my_posts as $post ) : setup_postdata($post);
if ( !has_post_thumbnail() ) {
continue;
} else {
?>
<li>
<div class="clearfix" >
<div class="thumb"><?php the_post_thumbnail('post-image-big'); ?></div>
<?php the_title(); ?>
<p class="category"><?php the_category(', '); ?></p>
</div>
</li>
<?php } ?>
<?php endforeach; ?>
</ul>

Answer 1

Try
$args = array( 'numberposts' => 5,
'orderby' => 'date',
'order' => 'DESC',
'post_type' => 'post',
'post_status' => 'publish' ,
'meta_query' => array(
array(
'key' => '_thumbnail_id',
'compare' => '!=',
'value' => ''
)
)
);
or this if checking for an empty string didn't work for you
$args = array( 'numberposts' => 5,
'orderby' => 'date',
'order' => 'DESC',
'post_type' => 'post',
'post_status' => 'publish' ,
'meta_query' => array(
array(
'key' => '_thumbnail_id',
'compare' => '!=',
'value' => null
)
)
);