최신글 썸네일 이미지 css관련 질문좀 드리겠습니다!

<ul id="gall_ul" class="gall_row">
        <?php for ($i=0; $i<count($list); $i++) {

            $classes = array();
            
            $classes[] = 'gall_li';
            $classes[] = 'col-gn-'.$bo_gallery_cols;

            if( $i && ($i % $bo_gallery_cols == 0) ){
                $classes[] = 'box_clear';
            }

            if( $wr_id && $wr_id == $list[$i]['wr_id'] ){
                $classes[] = 'gall_now';
            }
         ?>
        <li class="<?php echo implode(' ', $classes); ?>">
            <div class="gall_box">
                <div class="gall_chk">
                <?php if ($is_checkbox) { ?>
                <label for="chk_wr_id_<?php echo $i ?>" class="sound_only"><?php echo $list[$i]['subject'] ?></label>
                <input type="checkbox" name="chk_wr_id[]" value="<?php echo $list[$i]['wr_id'] ?>" id="chk_wr_id_<?php echo $i ?>">
                <?php } ?>
                <span class="sound_only">
                    <?php
                    if ($wr_id == $list[$i]['wr_id'])
                        echo "<span class=\"bo_current\">열람중</span>";
                    else
                        echo $list[$i]['num'];
                     ?>
                </span>
                </div>
                <div class="gall_con">
                    <div class="gall_img">
                        <a href="<?php echo $list[$i]['href'] ?>">
                        <?php
                        if ($list[$i]['is_notice']) { // 공지사항  ?>
                            <span class="is_notice">공지</span>
                        <?php } else {
                            $thumb = get_list_thumbnail($board['bo_table'], $list[$i]['wr_id'], $board['bo_gallery_width'], $board['bo_gallery_height'], false, true);

                            if($thumb['src']) {
                                $img_content = '<img src="'.$thumb['src'].'" alt="'.$thumb['alt'].'" >';
                            } else {
                                $img_content = '<span class="no_image">no image</span>';
                            }

                            echo $img_content;
                        }
                         ?>
                        </a>
                    </div>
                    <div class="gall_text_href">
                        <?php
                        // echo $list[$i]['icon_reply']; 갤러리는 reply 를 사용 안 할 것 같습니다. - 지운아빠 2013-03-04
                        if ($is_category && $list[$i]['ca_name']) {
                         ?>
                        <a href="<?php echo $list[$i]['ca_name_href'] ?>" class="bo_cate_link"><?php echo $list[$i]['ca_name'] ?></a>
                        <?php } ?>
                        <a href="<?php echo $list[$i]['href'] ?>" class="bo_tit">
                            <?php echo $list[$i]['subject'] ?>
                            <?php if ($list[$i]['comment_cnt']) { ?><span class="sound_only">댓글</span><span class="cnt_cmt">+ <?php echo $list[$i]['wr_comment']; ?></span><span class="sound_only">개</span><?php } ?>
                            <?php
                            // if ($list[$i]['file']['count']) { echo '<'.$list[$i]['file']['count'].'>'; }

                            if (isset($list[$i]['icon_new'])) echo rtrim($list[$i]['icon_new']);
                            if (isset($list[$i]['icon_hot'])) echo rtrim($list[$i]['icon_hot']);
                            //if (isset($list[$i]['icon_file'])) echo rtrim($list[$i]['icon_file']);
                            //if (isset($list[$i]['icon_link'])) echo rtrim($list[$i]['icon_link']);
                            if (isset($list[$i]['icon_secret'])) echo rtrim($list[$i]['icon_secret']);
                             ?>
                         </a>
                    </div>
                    <div class="gall_name">
                        <span class="sound_only">작성자 </span><span class="profile_img"><?php echo $list[$i]['name'] ?></span>
                    </div>
                    <div class="gall_info">
                        <span class="sound_only">조회 </span><i class="fa fa-eye" aria-hidden="true"></i> <?php echo $list[$i]['wr_hit'] ?>
                        <?php if ($is_good) { ?><span class="sound_only">추천</span><strong><i class="fa fa-thumbs-o-up" aria-hidden="true"></i> <?php echo $list[$i]['wr_good'] ?></strong><?php } ?>
                        <?php if ($is_nogood) { ?><span class="sound_only">비추천</span><strong><i class="fa fa-thumbs-o-down" aria-hidden="true"></i> <?php echo $list[$i]['wr_nogood'] ?></strong><?php } ?>
                        <span class="gall_date"><span class="sound_only">작성일 </span><i class="fa fa-clock-o" aria-hidden="true"></i> <?php echo $list[$i]['datetime2'] ?></span>
                    </div>
                </div>
            </div>
        </li>

        <!--추가된부분-->

        <?if($i%4==0){?>

        <div style="clear:both;"></div>

        <!-- clear:both로 안되시면 다른 br이나 내려주는 코드를 추가해주시면될거같아요! -->

        <?}?>

        <!--추가된부분-->
        <?php } ?>
        <?php if (count($list) == 0) { echo "<li class=\"empty_list\">게시물이 없습니다.</li>"; } ?>
    </ul>