<?php                        
$thumbnail_file = substr($list[$i]['wr_9'], 0, 4) == "http" ? $list[$i]['wr_9'] : substr(str_replace("/", "", str_replace("?playlist=", "", substr(explode("https://www.youtube.com/embed", $list[$i]['wr_content'])[1], 0, 21))), 0, 11);
if (empty($thumbnail_file)) {
    $thumbnail_extension = [".jpg", ".png", ".gif", "jpeg", ".mp4"];
    foreach ($list[$i]['file'] as $thumbnail) {
        if (in_array(strtolower(substr($thumbnail['file'], -4)), $thumbnail_extension)) {
            $thumbnail_file = $thumbnail['path']."/".$thumbnail['file'];
            break;
        }
        else $thumbnail_file = $board_skin_url."/no_image.jpg"; 
    }
}
$thumbnail_file = substr($thumbnail_file, 0, 4) == "http" ? $thumbnail_file : "https://img.youtube.com/vi/".$thumbnail_file."/sddefault.jpg";
echo strtolower(substr($thumbnail_file, -4)) == ".mp4" ? "<video class='thumbnail-img-mp4' src='".$thumbnail_file."' autoplay loop muted></video>" : "<img class='thumbnail-img-mp4' src='".$thumbnail_file."'>";
?>