diff --git a/lib/thumbnail.lib.php b/lib/thumbnail.lib.php
new file mode 100644
index 000000000..f9e099cb3
--- /dev/null
+++ b/lib/thumbnail.lib.php
@@ -0,0 +1,77 @@
+<?php
+if (!defined('_GNUBOARD_')) exit;
+
+@ini_set('memory_limit', '512M');
+
+function thumbnail($bo_table, $file, $width, $height, $is_create=false)
+{
+    global $g4;
+
+    $thumb_dir = "$g4[path]/data/thumb/$bo_table";
+    if (!is_dir($thumb_dir)) {
+        @mkdir($thumb_dir, 0707);
+        @chmod($thumb_dir, 0707);
+    }
+    $thumb_file = "$thumb_dir/{$width}x{$height}_{$file}.png";
+    $thumb_time = @filemtime($thumb_file);
+    $source_file = "$g4[path]/data/file/$bo_table/$file";
+    $source_time = @filemtime($source_file);
+    if (file_exists($thumb_file)) {
+        if ($is_create == false && $source_time < $thumb_time) {
+            return $thumb_file;
+        }
+    }
+
+    $size = @getimagesize($source_file);
+    // 이미지 파일이 없거나 아님
+    if (!$size[0]) {
+        if (!$height) $height = $width;
+        $thumb_file = "$g4[path]/data/thumb/{$width}x{$height}_noimg.gif";
+        if (!file_exists($thumb_file)) {
+            $target = imagecreate($width, $height);
+            imagecolorallocate($target, 250, 250, 250);
+            imagecopy($target, $target, 0, 0, 0, 0, $width, $height);
+            imagepng($target, $thumb_file, 0);
+            @chmod($thumb_file, 0606); // 추후 삭제를 위하여 파일모드 변경
+        }
+        return $thumb_file;
+    }
+
+    $is_imagecopyresampled = false;
+    $is_large = false;
+
+    $src = null;
+    if ($size[2] == 1) {
+        $src = imagecreatefromgif($source_file);
+    } else if ($size[2] == 2) {
+        $src = imagecreatefromjpeg($source_file);
+    } else if ($size[2] == 3) {
+        $src = imagecreatefrompng($source_file);
+    }
+
+    if ($width) {
+        if ($height) {
+            $rate = $width / $size[0];
+            $tmp_height = (int)($size[1] * $rate);
+            if ($tmp_height < $height) {
+                $dst = imagecreatetruecolor($width, $height);
+                $bgcolor = imagecolorallocate($dst, 250, 250, 250); // 배경색 여기야!!!
+                imagefill($dst, 0, 0, $bgcolor);
+                imagecopyresampled($dst, $src, 0, 0, 0, 0, $width, $tmp_height, $size[0], $size[1]);
+            } else {
+                $dst = imagecreatetruecolor($width, $height);
+                imagecopyresampled($dst, $src, 0, 0, 0, 0, $width, $tmp_height, $size[0], $size[1]);
+            }
+        } else {
+            $rate = $width / $size[0];
+            $tmp_height = (int)($size[1] * $rate);
+            $dst = imagecreatetruecolor($width, $tmp_height);
+            imagecopyresampled($dst, $src, 0, 0, 0, 0, $width, $tmp_height, $size[0], $size[1]);
+        }
+    }
+
+    imagepng($dst, $thumb_file, 0); // 0 (no compression) ~ 9
+    chmod($thumb_file, 0606); // 추후 삭제를 위하여 파일모드 변경
+    return $thumb_file;
+}
+?>
\ No newline at end of file