<?php
/**
* Grab the url of a publicly embeddable video hosted on vimeo
* @param str $video_url The "embed" url of a video
* @return str The url of the thumbnail, or false if there's an error
*/
function grab_vimeo_thumbnail($vimeo_url){
if( !$vimeo_url ) return false;
$data = json_decode( file_get_contents( 'http://vimeo.com/api/oembed.json?url=' . $vimeo_url ) );
if( !$data ) return false;
return $data->thumbnail_url;
}