vimeo.php

<?php 

$src = 'http://player.vimeo.com/video/1234';

preg_match('!video\/([0-9]+)!i', $src, $match);

$id       = $match[1];
$apiurl   = 'http://vimeo.com/api/v2/video/' . $id . '.json';
$response = file_get_contents($apiurl);
$json     = json_decode($response, true);

print_r($json[0]['thumbnail_large']);