[html] Get img thumbnails from Vimeo?

2020 solution:

I wrote a PHP function which uses the Vimeo Oembed API.

/**
 * Get Vimeo.com video thumbnail URL
 *
 * Set the referer parameter if your video is domain restricted.
 * 
 * @param  int    $videoid   Video id
 * @param  URL    $referer   Your website domain
 * @return bool/string       Thumbnail URL or false if can't access the video
 */
function get_vimeo_thumbnail_url( $videoid, $referer=null ){

    // if referer set, create context
    $ctx = null;
    if( isset($referer) ){
        $ctxa = array(
            'http' => array(
                'header' => array("Referer: $referer\r\n"),
                'request_fulluri' => true,
            ),
        );
        $ctx = stream_context_create($ctxa);
    }

    $resp = @file_get_contents("https://vimeo.com/api/oembed.json?url=https://vimeo.com/$videoid", False, $ctx);
    $resp = json_decode($resp, true);

return $resp["thumbnail_url"]??false;
}

Usage:

echo get_vimeo_thumbnail_url("1084537");