CSS 메인 사진 크기 설정 질문입니다.

<?phpif (!defined("_GNUBOARD_")) exit; // 개별 페이지 접근 불가if(G5_IS_MOBILE) {    include_once(G5_THEME_MSHOP_PATH.'/shop.head.php');    return;}include_once(G5_THEME_PATH.'/head.sub.php');include_once(G5_LIB_PATH.'/outlogin.lib.php');include_once(G5_LIB_PATH.'/poll.lib.php');include_once(G5_LIB_PATH.'/visit.lib.php');include_once(G5_LIB_PATH.'/connect.lib.php');include_once(G5_LIB_PATH.'/popular.lib.php');include_once(G5_LIB_PATH.'/latest.lib.php');?><!-- 상단 시작 { --><div id="hd">    <h1 id="hd_h1"><?php echo $g5['title'] ?></h1>    <div id="skip_to_container"><a href="#container">본문 바로가기</a></div>    <?php if(defined('_INDEX_')) { // index에서만 실행        include G5_BBS_PATH.'/newwin.inc.php'; // 팝업레이어     } ?>    <aside id="hd_qnb">        <h2>쇼핑몰 퀵메뉴</h2>        <div>            <a href="<?php echo G5_SHOP_URL; ?>/cart.php"><img src="<?php echo G5_SHOP_URL; ?>/img/hd_nb_cart.gif" alt="장바구니"></a>            <a href="<?php echo G5_SHOP_URL; ?>/wishlist.php"><img src="<?php echo G5_SHOP_URL; ?>/img/hd_nb_wish.gif" alt="위시리스트"></a>            <a href="<?php echo G5_SHOP_URL; ?>/orderinquiry.php"><img src="<?php echo G5_SHOP_URL; ?>/img/hd_nb_deli.gif" alt="주문/배송조회"></a>        </div>    </aside>    <div id="hd_wrapper">        <div id="logo"><a href="<?php echo G5_SHOP_URL; ?>/"><img src="<?php echo G5_DATA_URL; ?>/common/logo_img" alt="<?php echo $config['cf_title']; ?>"></a></div>        <div id="hd_sch">            <h3>쇼핑몰 검색</h3>            <form name="frmsearch1" action="<?php echo G5_SHOP_URL; ?>/search.php" onsubmit="return search_submit(this);">            <label for="sch_str" class="sound_only">검색어<strong class="sound_only"> 필수</strong></label>            <input type="text" name="q" value="<?php echo stripslashes(get_text(get_search_string($q))); ?>" id="sch_str" required>            <input type="submit" value="검색" id="sch_submit">            </form>            <script>            function search_submit(f) {                if (f.q.value.length < 2) {                    alert("검색어는 두글자 이상 입력하십시오.");                    f.q.select();                    f.q.focus();                    return false;                }                return true;            }            </script>        </div>        <div id="tnb">            <h3>회원메뉴</h3>            <ul>                <?php if ($is_member) { ?>                <?php if ($is_admin) {  ?>                <li><a href="<?php echo G5_ADMIN_URL; ?>/shop_admin/"><b>관리자</b></a></li>                <?php }  ?>                <li><a href="<?php echo G5_BBS_URL; ?>/member_confirm.php?url=register_form.php">정보수정</a></li>                <li><a href="<?php echo G5_BBS_URL; ?>/logout.php?url=shop">로그아웃</a></li>                <?php } else { ?>                <li><a href="<?php echo G5_BBS_URL; ?>/register.php">회원가입</a></li>                <li><a href="<?php echo G5_BBS_URL; ?>/login.php?url=<?php echo $urlencode; ?>"><b>로그인</b></a></li>                <?php } ?>                <li><a href="<?php echo G5_SHOP_URL; ?>/mypage.php">마이페이지</a></li>                <li><a href="<?php echo G5_BBS_URL; ?>/faq.php">FAQ</a></li>                <li><a href="<?php echo G5_BBS_URL; ?>/qalist.php">1:1문의</a></li>                <li><a href="<?php echo G5_SHOP_URL; ?>/personalpay.php">개인결제</a></li>                <li><a href="<?php echo G5_SHOP_URL; ?>/itemuselist.php">사용후기</a></li>                <?php if(G5_COMMUNITY_USE) { ?>                <li><a href="<?php echo G5_URL; ?>/">커뮤니티</a></li>                <?php } ?>            </ul>        </div>    </div></div><div id="wrapper">    <?php include(G5_SHOP_SKIN_PATH.'/boxtodayview.skin.php'); // 오늘 본 상품 ?>    <div id="aside">        <?php echo outlogin('theme/shop_basic'); // 아웃로그인 ?>        <?php include_once(G5_SHOP_SKIN_PATH.'/boxcategory.skin.php'); // 상품분류 ?>        <?php include_once(G5_SHOP_SKIN_PATH.'/boxcart.skin.php'); // 장바구니 ?>        <?php include_once(G5_SHOP_SKIN_PATH.'/boxwish.skin.php'); // 위시리스트 ?>        <?php include_once(G5_SHOP_SKIN_PATH.'/boxevent.skin.php'); // 이벤트 ?>        <?php include_once(G5_SHOP_SKIN_PATH.'/boxcommunity.skin.php'); // 커뮤니티 ?>        <!-- 쇼핑몰 배너 시작 { -->        <?php echo display_banner('왼쪽'); ?>        <!-- } 쇼핑몰 배너 끝 -->    </div><!-- } 상단 끝 -->    <!-- 콘텐츠 시작 { -->    <div id="container">        <?php if ((!$bo_table || $w == 's' ) && !defined('_INDEX_')) { ?><div id="wrapper_title"><?php echo $g5['title'] ?></div><?php } ?>        <!-- 글자크기 조정 display:none 되어 있음 시작 { -->        <div id="text_size">            <button class="no_text_resize" onclick="font_resize('container', 'decrease');">작게</button>            <button class="no_text_resize" onclick="font_default('container');">기본</button>            <button class="no_text_resize" onclick="font_resize('container', 'increase');">크게</button>        </div>        <!-- } 글자크기 조정 display:none 되어 있음 끝 -->