diff --git a/lib/thumb.lib.php b/lib/thumb.lib.php
new file mode 100644
index 000000000..5d4a24f99
--- /dev/null
+++ b/lib/thumb.lib.php
@@ -0,0 +1,128 @@
+<?
+if (!defined('_GNUBOARD_')) exit;
+
+/*******************************************************************************
+    썸네일 Class
+
+    사용법 : 
+    
+    $thumb = new g4_thumbnail(경로, 썸네일이미지폭);
+    $thumb->run(이미지 경로가 포함된 컨텐츠);
+
+*******************************************************************************/
+class g4_thumb {
+    var $path;
+    var $width;
+    var $red = 0xff;
+    var $green = 0xff;
+    var $blue = 0xff;
+    var $quality = 100;
+    var $permission = 0606;
+
+    function g4_thumb($path, $width) {
+        $this->set_path($path);
+        $this->set_width($width);
+    }
+
+    // 경로
+    function set_path($path) {
+        $this->path = $path;
+        @mkdir($path, 0707);
+        @chmod($path, 0707);
+    }
+
+    function set_width($width) {
+        $this->width = $width;
+    }
+
+    function get_width() {
+        return $this->width;
+    }
+
+    function set_bgcolor($red, $green, $blue) {
+        $this->red   = $red;
+        $this->green = $green;
+        $this->blue  = $blue;
+    }
+
+    function set_quality($quality) {
+        $this->quality = $quality;
+    }
+
+    function set_permission($permission) {
+        $this->permission = $permission;
+    }
+
+    function create($srcimg, $thumbfile) {
+        $width = $this->get_width();
+        $source = null;
+        $size = @getimagesize($srcimg);
+        if ($size[2] == 1) 
+            $source = @imagecreatefromgif($srcimg);
+        else if ($size[2] == 2)
+            $source = @imagecreatefromjpeg($srcimg);
+        else if ($size[2] == 3) 
+            $source = @imagecreatefrompng($srcimg);
+
+        if ($source == null)
+            return '';
+
+        // 이미지의 폭이 설정폭 보다 작다면
+        if ($size[0] < $width) {
+            $width  = $size[0];
+            $height = $size[1];
+        } else {
+            $rate = $width / $size[0];
+            $height = (int)($size[1] * $rate);
+        }
+
+        $target = @imagecreatetruecolor($width, $height);
+        $bgcolor = @imagecolorallocate($target, $this->red, $this->green, $this->blue); // 썸네일 배경
+        imagefilledrectangle($target, 0, 0, $width, $height, $bgcolor);
+        imagecopyresampled($source, $source, 0, 0, 0, 0, $width, $height, $size[0], $size[1]);
+        imagecopy($target, $source, 0, 0, 0, 0, $size[0], $size[1]);
+        imagejpeg($target, $thumbfile, $this->quality);
+        chmod($thumbfile, $this->permission); // 추후 삭제를 위하여 파일모드 변경
+        return $thumbfile;
+    }
+
+    function thumbnail($matches)
+    {
+        foreach ($matches as $img) {
+            preg_match("/src=[\"\']?([^\"\'\s>]+)/i", $img, $m);
+            $src = trim($m[1]);
+
+            $result = true;
+            if (preg_match("/\.(jpe?g|png|gif)$/i", $src)) {
+                // 유일한 파일명을 만든다.
+                $filename = md5($src).'_'.$this->width;
+                $thumb = $this->path.'/'.$filename;
+
+                if (!file_exists($thumb)) {
+                    $result = $this->create($src, $thumb);
+                }
+            }
+            else {
+                $thumb = $src;
+            }
+
+            if ($result) {
+                $size = @getimagesize($src);
+                if ($size[0] < $this->width) {
+                    return "<img src='$thumb' width='$size[0]' />";
+                } else {
+                    return "<a href='$src' target='_blank' title='클릭하시면 이미지가 크게 보입니다.'><img src='$thumb' width='{$this->width}' border='0' /></a>";
+                }
+            }
+        }
+    }
+
+    function run($content)
+    {
+        //return preg_replace_callback('#<img[^>]+>#iS', create_function('$matches', 'return g4_thumb::thumbnail($matches);'), $content);
+        //return preg_replace_callback('#<img[^>]+>#iS', array('g4_thumb', 'thumbnail'), $content);
+        //return preg_replace_callback('#<img[^>]+>#iS', 'g4_thumb::thumbnail', $content);
+        return preg_replace_callback('#<img[^>]+>#iS', array($this, 'thumbnail'), $content);
+    }
+}
+?>
\ No newline at end of file