Hi:

Maybe is a little over kill, but i need to use a URL to upload a video preview url (right know, a Youtube Preview image)
Im already can obtain the URL, but i need to insert as a Thumbnail image, so i can use it as preview image in the archive.
But, i can found how to do that.
I think maybe i can use that url as a base to the upload function, but im stuck.
Any help could be appreciate.
The Code i have.

piklist (
    'field',
    array(
        'type' => 'text',
        'scope' => 'post_meta',
        'field' => 'imgd_programa_video',
        'label' => __('Link Youtube', 'imgd'),
        'value' => '',
        'attributes' => array(
            'class' => 'text'
        ),
        'position' => 'wrap'
    )
);

?>
<script>
jQuery(document).ready(function( $ ) {
  $("#_post_meta_imgd_programa_video_0").on('change',function () {
     var ytl = $( "#_post_meta_imgd_programa_video_0" ).val();
     var yti = ytl.match(/(?:https?:\/{2})?(?:w{3}\.)?youtu(?:be)?\.(?:com|be)(?:\/watch\?v=|\/)([^\s&]+)/);

//This is the post thumbnail, but...
     $('_post_meta__thumbnail_id_0').value("http://i3.ytimg.com/vi/"+ yti[1] + "/hqdefault.jpg");
     
  });
});
</script>

<?php

piklist('field', array(
    'type' => 'file'
    ,'field' => '_thumbnail_id' // Use these field to match WordPress featured images.
    ,'scope' => 'post_meta'
    ,'options' => array(
        'title' => __('Imagenes del Show', 'imgd')
        ,'button' => __('Inserte las imagenes', 'imgd')
    )
));