How to Make Only Images Connected to a Post Show? Not Entire Media Collection?

    add_action( 'admin_footer-post-new.php', 'firmasite_mediapanel_lock_uploaded' );
    add_action( 'admin_footer-post.php', 'firmasite_mediapanel_lock_uploaded' );
    function firmasite_mediapanel_lock_uploaded() { ?>
  <script type="text/javascript">
    jQuery(document).on("DOMNodeInserted", function(){
        // Lock uploads to "Uploaded to this post"
        jQuery('select.attachment-filters [value="uploaded"]').attr( 'selected', true ).parent().trigger('change');
    });
  </script>
<?php }

Just place that into your child-theme’s functions.php file 🙂