영카트 후기 썸네일 이미지를 변경하고싶습니다.

// 사용후기 썸네일 생성function get_itemuselist_thumbnail($it_id, $contents, $thumb_width, $thumb_height, $is_create=false, $is_crop=true, $crop_mode='center', $is_sharpen=true, $um_value='80/0.5/3'){    global $g5, $config;    $img = $filename = $alt = "";     if($contents) {        $matches = get_editor_image($contents, false);         for($i=0; $i<count($matches[1]); $i++)        {            // 이미지 path 구함            $p = parse_url($matches[1][$i]);            if(strpos($p['path'], '/'.G5_DATA_DIR.'/') != 0)                $data_path = preg_replace('/^\/.*\/'.G5_DATA_DIR.'/', '/'.G5_DATA_DIR, $p['path']);            else                $data_path = $p['path'];             $srcfile = G5_PATH.$data_path;             if(preg_match("/\.({$config['cf_image_extension']})$/i", $srcfile) && is_file($srcfile)) {                $size = @getimagesize($srcfile);                if(empty($size))                    continue;                 $filename = basename($srcfile);                $filepath = dirname($srcfile);                 preg_match("/alt=[\"\']?([^\"\']*)[\"\']?/", $matches[0][$i], $malt);                $alt = get_text($malt[1]);                 break;            }        }        if($filename) {            $thumb = thumbnail($filename, $filepath, $filepath, $thumb_width, $thumb_height, $is_create, $is_crop, $crop_mode, $is_sharpen, $um_value);             if($thumb) {                $src = G5_URL.str_replace($filename, $thumb, $data_path);                $img = '<img src="'.$src.'" width="'.$thumb_width.'" height="'.$thumb_height.'" alt="'.$alt.'">';            }        }    }    if(!$img)        $img = get_it_image($it_id, $thumb_width, $thumb_height);     return $img;}

<?php echo get_itemuselist_thumbnail($row['it_id'], $row['is_content'], 50, 50); ?>