// 썸네일 생성.. 080408, curlychoi
function mw_make_thumbnail($set_width, $set_height, $source_file, $thumbnail_file='', $keep=false)
{
    global $mw_basic;

    if (!$thumbnail_file)
        $source_file = $thumbnail_file;

    $size = @getimagesize($source_file);

    switch ($size[2]) {
        case 1: $source = @imagecreatefromgif($source_file); break;
        case 2: $source = @imagecreatefromjpeg($source_file); break;
        case 3: $source = @imagecreatefrompng($source_file); break;
        default: return false;
    }

    if ($keep)
    {
$keep_size = mw_thumbnail_keep($size, $set_width, $set_height);
$set_width = $get_width = $keep_size[0];
$set_height = $get_height = $keep_size[1];
    }
    else
    {
        $rate = $set_width / $size[0];
        $get_width = $set_width;
        $get_height = (int)($size[1] * $rate);

        if ($get_height < $set_height) {
            //$get_width = $set_width + $set_height - $get_height;
            //$get_height = $set_height;
            $rate = $set_height / $size[1];
            $get_height = $set_height;
            $get_width = (int)($size[0] * $rate);
        }     
    }

    $target = @imagecreatetruecolor($set_width, $set_height);
    $white = @imagecolorallocate($target, 255, 255, 255);
    @imagefilledrectangle($target, 0, 0, $set_width, $set_height, $white);
    @imagecopyresampled($target, $source, 0, 0, 0, 0, $get_width, $get_height, $size[0], $size[1]);

    if ($mw_basic[cf_watermark_use_thumb] && file_exists($mw_basic[cf_watermark_path])) { // watermark
        mw_watermark($target, $set_width, $set_height
            , $mw_basic[cf_watermark_path]
            , $mw_basic[cf_watermark_position]
            , $mw_basic[cf_watermark_transparency]);
    }

    @imagejpeg($target, $thumbnail_file, 100);
    @chmod($thumbnail_file, 0606);

    @imagedestroy($target);
    @imagedestroy($source);
}


이게 기본적은 썸네일 생성 합수인것 같은데요..

여기에 썸네일을  중간 기준으로  crop 을 할려면 어떻게 수정을 해야하는지 도움좀 주세요~