일반페이지에서 thumbnail 함수를 이용한 썸네일 생성이 안됨

<?php

    $sql = "SELECT * FROM g5_write_게시판 이름";

    $result = sql_query($sql);

    while ($row = sql_fetch_array($result)) {

        $wr_id = $row['wr_id'];

        $wr_subject = $row['wr_subject'];

        $wr_1 = $row['wr_1'];

 

        // wr_1 이미지 추출

        preg_match('/<img[^>]+src=["\']([^"\']+)["\']/', $wr_1, $matches);

        $img_path = isset($matches[1]) ? $matches[1] : null;

        $img_name = basename($img_path);

        $dir_path = dirname($img_path);

 

        if ($img_path) {

            $thumb_path = thumbnail($img_name, $dir_path, G5_DATA_PATH . '/썸네일 저장 폴더', 856, 671, false);

            $thumb_url = G5_DATA_URL . '/썸네일 저장 폴더/' . $thumb_path;

        } else {

            $thumb_url = G5_URL . '/images/no_img.jpg';

        }

?>

        <a href="<?php echo G5_URL.'/projectView.php?wr_id='.$wr_id; ?>" class="project">

            <div class="img-wrap">

                <img src="<?php echo $thumb_url; ?>" alt="<?php echo $wr_subject; ?>" loading="lazy" />

            </div>

            <div class="title-wrap">

                <h3><?php echo conv_content(preg_replace("@<.*?>@","", $wr_subject),0);?></h3>

            </div>

        </a>

<?php } ?>