위의 것은 만도님 답사기 스킨에서 gblist.skin.php 부분을 제가 조금 변형한 것입니다.
if ($row[wf_id] < 12 ) {
위 부분의 12를 출력하고자 하는 숫자로 고치면 아마 될 겁니다.

그럼 제가 쓴 방법으로 올려드립니다.
<?
if (!defined("_GNUBOARD_")) exit; // 개별 페이지 접근 불가

if (!$skin_no) $skin_no = "01";

$file_table = "$cfg[write_table_prefix]{$bo_table}_file";

function get_thumb_filename2($num, $seq)
{
    return sprintf("%05d", $num) . "_" . sprintf("%03d", $seq);}

?>

<link rel='stylesheet' href='<?=$board_skin?>/style<?=$skin_no?>.css' type='text/css'>

<table width='99%' align=center border=0 cellpadding=0 cellspacing=0><tr><td>

<table width='100%' bgcolor=#FFFFFF cellpadding=4 align=center>
<tr>
    <form name=fcategory method=get action='<?="./"?>'>
    <input type=hidden name=doc value='<?=$doc?>'>
    <td width=50%>
        <? if ($is_category) { ?>
            <select name=ca_id onchange="location='<?=$category_location?>'+this.value;" class=select>
            <option value=''>전체</option>
            <?=$category_option?>
            </select>
        <? } ?>

    <a href='http://nemoddol.net/gnu/?doc=bbs/gnuboard.php&bo_table=phonephoto'>*_<font color=purple>이전 갤러리로</font>_*</a>
    </td>
    </form>
    <td width=50% align=right>
<SCRIPT language="JavaScript">
<!--
function OpenWin(){
win=window.open("http://nemoddol.net/gnu/?doc=slide2.php","new","width=750, height=600");
}
// -->
</SCRIPT>

    <span class=etc onclick='OpenWin();' style='cursor=hand'><font color='#E58B31'>슬라이드쇼</font></span>&nbsp;&nbsp;
    Total <?=nf($total_count)?>건
    <? if ($admin_href) { echo "<a href='$admin_href'><img src='$board_skin/icon_admin.gif' border=0 align=absmiddle></a>"; } ?>




</td>
</tr>
</table>

<table width='100%' border=0 cellpadding=0 cellspacing=0  bgcolor=#FFFFFF>
<form name=frmgblist method='post' action=''>
<input type=hidden name=bo_table value='<?=$bo_table?>'>
<input type=hidden name=sselect  value='<?=$sselect?>'>
<input type=hidden name=stext    value='<?=$stext?>'>
<input type=hidden name=section  value='<?=$section?>'>
<input type=hidden name=page    value='<?=$page?>'>
<input type=hidden name=sw      value=''>
<tr><td colspan=15 class=line></td></tr>
<tr class=bt>
    <td width=50><?=subject_sort_link('wr_num', $qstr2)?><span class=bh>No</span></a></td>
    <td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td>
    <? if ($is_category) { ?><td width=60><?=subject_sort_link('ca_id', $qstr2)?><span class=bh>Category</span></a></td><td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td><? } ?>
    <td><?=subject_sort_link('wr_subject', $qstr2)?><span class=bh>Title</span></a></td>
    <td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td>
    <td width=100><?=subject_sort_link('wr_name', $qstr2)?><span class=bh>Name</span></a></td>
    <td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td>
    <td width=60><?=subject_sort_link('wr_datetime', $qstr2)?><span class=bh>Date</span></a></td>
    <td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td>
    <td width=50><?=subject_sort_link('wr_hit', $qstr2)?><span class=bh>Hits</span></a></td>
    <? if ($is_good) { ?><td><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td><td width=40><?=subject_sort_link('wr_good', $qstr2)?><span class=bh>Good</span></a></td><? } ?>
    <? if ($is_nogood) { ?><td width=1><img src='<?=$board_skin?>/split<?=$skin_no?>.gif'></td><td width=50><?=subject_sort_link('wr_nogood', $qstr2)?><span class=bh>Nogood</span></a></td><? } ?>
</tr>
<?
// 번호에 이미지를 사용할 경우는 아래의 주석을 제거하고 $list[$i][num]의 내용을 수정후 사용하세요.
// if (!is_int($list[$i][num])) { $list[$i][num] = "<img src='$board_skin/img/arrow.gif'>"; }
?>
<?
for ($i=0; $i<count($list); $i++) {
    if ($i > 0) {
        echo "<tr><td colspan=15 background='$board_skin/dotline.gif' height=1></td></tr>";
    }
?>
<? if ($list[$i][num] == '공지') { $list[$i][num] = "<img src='$board_skin/icon_notice.gif' border=0>"; } // 공지를 이미지로 변환 ?>
<? if ($list[$i][num] == '<font color=crimson><b>→</b></font>') { $list[$i][num] = "<img src='$board_skin/icon_arrow.gif' border=0>"; } // 화살표표시를 이미지로 변환 ?>
<tr align=center>
    <td height=25 colspan=2><?=$list[$i][num]?></td>
    <? if ($is_category) { ?><td colspan=2><?=$list[$i][ca_name]?></td><? } ?>
    <td align=left>
        <? if ($is_checkdelete) { ?><input type=checkbox name=chk_wr_id[] value='<?=$list[$i][wr_id]?>'><? } ?>&nbsp;
        <?=$list[$i][reply]?>
        <?=$list[$i][icon_reply]?>
        <a href='<?=$list[$i][href]?>'><? if ($list[$i][is_notice]) echo "<b><span class=notice>"; ?><?=$list[$i][subject]?><? if ($list[$i][is_notice]) echo "</span></b>"; ?></a>
        <?=$list[$i][commentcnt]?>
        <?=$list[$i][icon_file]?>
        <?=$list[$i][icon_link]?>
        <?=$list[$i][icon_new]?>
        <?=$list[$i][icon_hot]?>
        <?=$list[$i][icon_battle]?>
        <?=$list[$i][icon_secret]?></td>
    <td nowrap colspan=3><?=$list[$i][name]?></td>
    <td colspan=2><?=$list[$i][datetime]?></td>
    <td colspan=2><?=$list[$i][wr_hit]?></td>
    <? if ($is_good) { ?><td colspan=2><?=$list[$i][wr_good]?></td><? } ?>
    <? if ($is_nogood) { ?><td><?=$list[$i][wr_nogood]?></td><? } ?>
</tr>
<tr>

<td colspan=2></td>
<td colspan=13 align=left>&nbsp;&nbsp;&nbsp;
<?

$wr_id=$list[$i][wr_id];
$sql = " select * from $file_table where wr_id = '$wr_id' order by wf_id";
$result = sql_query($sql);

for ($j=0; $row=mysql_fetch_array($result); $j++){
$file_name = get_thumb_filename2($wr_id,  $row[wf_id]);
$file = "./data/file/$bo_table/{$file_name}_s.jpg";
$cont=cut_str(get_text($row[wf_cont]),30);
$ss=$list[$i][wr_id];

if ($row[wf_id] < 12 ) {
echo "<a href='./?doc=bbs/gnuboard.php&bo_table=$bo_table&wr_id=$ss'><img src='$file' width=40 border=0 alt='$cont'></a>&nbsp;";
}

else echo "";

}
?>

만도님 스킨을 참고하시면...