Vimeo thumbnails

Maybe this can help

$videoID = the_field('video_link');
$jsonurl="http://vimeo.com/api/v2/video/".$videoID.'.json';
$json = file_get_contents($jsonurl,0,null,null);
$json_output = json_decode($json,true);
echo '<img src="'. $json_output[0]['thumbnail_large'] .'" />';

It’s the same call using json method