I Use Advanced Custom Fields Plugin to add an ID
and use this code in my loop-blog.php
<?php if ( has_post_thumbnail() ) {
the_post_thumbnail();
} else { ?>
<img src="https://www.image.com/<?php the_field('img_id'); ?>.png"
alt="<?php the_title(); ?>" />
<?php } ?>
in post have no Featured Image!
Gives a way to work with SNAP?