diff --git a/lib/thumbnail.lib.php b/lib/thumbnail.lib.php
index 7f95f82b5..8f52de5b9 100644
--- a/lib/thumbnail.lib.php
+++ b/lib/thumbnail.lib.php
@@ -158,54 +158,45 @@ function get_view_thumbnail($contents)
     return $contents;
 }
 
-//function thumbnail($bo_table, $file, $width, $height, $is_create=false)
-function thumbnail($filename, $source_path, $target_path, $thumb_width, $thumb_height, $is_create, $is_crop=false)
+function thumbnail($filename, $source_path, $target_path, $thumb_width, $thumb_height, $is_create, $is_crop=false, $crop_mode='center', $is_sharpen=true, $um_value='80/0.5/3')
 {
     global $g4;
 
-    if ($thumb_width==0 || $thumb_height==0) return;
+    if(!$thumb_width && !$thumb_height)
+        return;
 
     $thumb_filename = preg_replace("/\.[^\.]+$/i", "", $filename); // 확장자제거
+    $thumb_file = "$target_path/thumb-{$thumb_filename}_{$thumb_width}x{$thumb_height}.jpg";
+    $source_file = "$source_path/$filename";
+
+    if(!is_file($source_file)) // 원본 파일이 없다면
+        return;
+
+    $size = @getimagesize($source_file);
+    if($size[2] < 1 || $size[2] > 3) // gif, jpg, png 에 대해서만 적용
+        return;
 
     if (!is_dir($target_path)) {
         @mkdir($target_path, 0707);
         @chmod($target_path, 0707);
     }
 
-    $thumb_file = "$target_path/thumb-{$thumb_filename}_{$thumb_width}x{$thumb_height}.jpg";
+    // Animated GIF는 썸네일 생성하지 않음
+    if($size[2] == 1) {
+        if(is_animated_gif($source_file))
+            return;
+    }
+
     $thumb_time = @filemtime($thumb_file);
-    $source_file = "$source_path/$filename";
     $source_time = @filemtime($source_file);
+
     if (file_exists($thumb_file)) {
         if ($is_create == false && $source_time < $thumb_time) {
             return basename($thumb_file);
         }
     }
 
-    $size = @getimagesize($source_file);
-    // 이미지 파일이 없거나 아님
-    if (!$size[0]) {
-        if (!$thumb_height) $thumb_height = $thumb_width;
-        $thumb_file = "$target_path/thumb-noimg_{$thumb_width}x{$thumb_height}.jpg";
-        if (!file_exists($thumb_file)) {
-            $target = imagecreate($thumb_width, $thumb_height);
-            imagecolorallocate($target, 250, 250, 250);
-            imagecopy($target, $target, 0, 0, 0, 0, $thumb_width, $thumb_height);
-            imagejpeg($target, $thumb_file, 90);
-            @chmod($thumb_file, 0606); // 추후 삭제를 위하여 파일모드 변경
-        }
-        return basename($thumb_file);
-    }
-
-    // Animated GIF 체크
-    if($size[2] == 1) {
-        if(is_animated_gif($source_file))
-            return basename($source_file);
-    }
-
-    $is_imagecopyresampled = false;
-    $is_large = false;
-
+    // 원본파일의 GD 이미지 생성
     $src = null;
     if ($size[2] == 1) {
         $src = imagecreatefromgif($source_file);
@@ -220,46 +211,271 @@ function thumbnail($filename, $source_path, $target_path, $thumb_width, $thumb_h
     if(!$src)
         return;
 
-    $src_width = $size[0];
-    $src_height = $size[1];
-
-    if($is_crop && $thumb_width && $thumb_height) {
-        $ratio = $thumb_height / $thumb_width;
-        if($src_height / $src_width >= $ratio) {
-            $src_height = ceil(($thumb_height * $src_width) / $thumb_width);
+    $is_large = true;
+    // width, height 설정
+    if($thumb_width) {
+        if(!$thumb_height) {
+            $thumb_height = round(($thumb_width * $size[1]) / $size[0]);
         } else {
-            $src_width = ceil(($thumb_width * $src_height) / $thumb_height);
+            if($size[0] < $thumb_width || $size[1] < $thumb_height)
+                $is_large = false;
+        }
+    } else {
+        if($thumb_height) {
+            $thumb_width = round(($thumb_height * $size[0]) / $size[1]);
         }
     }
 
-    if ($thumb_width) {
-        if ($thumb_height) {
-            $rate = $thumb_width / $src_width;
-            $tmp_height = (int)($src_height * $rate);
-            if ($tmp_height < $thumb_height) {
-                $dst = imagecreatetruecolor($thumb_width, $thumb_height);
-                $bgcolor = imagecolorallocate($dst, 250, 250, 250); // 배경색 여기야!!!
-                imagefill($dst, 0, 0, $bgcolor);
-                imagecopyresampled($dst, $src, 0, 0, 0, 0, $thumb_width, $thumb_height, $src_width, $src_height);
-            } else {
-                $dst = imagecreatetruecolor($thumb_width, $thumb_height);
-                imagecopyresampled($dst, $src, 0, 0, 0, 0, $thumb_width, $thumb_height, $src_width, $src_height);
+    $dst_x = 0;
+    $dst_y = 0;
+    $src_x = 0;
+    $src_y = 0;
+    $dst_w = $thumb_width;
+    $dst_h = $thumb_height;
+    $src_w = $size[0];
+    $src_h = $size[1];
+
+    $ratio = $dst_h / $dst_w;
+
+    if($is_large) {
+        // 크롭처리
+        if($is_crop) {
+            switch($crop_mode)
+            {
+                case 'center':
+                    if($size[1] / $size[0] >= $ratio) {
+                        $src_h = round($src_w * $ratio);
+                        $src_y = round(($size[1] - $src_h) / 2);
+                    } else {
+                        $src_w = round($size[1] / $ratio);
+                        $src_x = round(($size[0] - $src_w) / 2);
+                    }
+                    break;
+                default:
+                    if($size[1] / $size[0] >= $ratio) {
+                        $src_h = round($src_w * $ratio);
+                    } else {
+                        $src_w = round($size[1] / $ratio);
+                    }
+                    break;
             }
         } else {
-            $rate = $thumb_width / $src_width;
-            $tmp_height = (int)($src_height * $rate);
-            $dst = imagecreatetruecolor($thumb_width, $tmp_height);
-            imagecopyresampled($dst, $src, 0, 0, 0, 0, $thumb_width, $tmp_height, $src_width, $src_height);
+            if($size[1] / $size[0] >= $ratio) {
+                $src_h = round($src_w * $ratio);
+            } else {
+                $src_w = round($size[1] / $ratio);
+            }
         }
+
+        $dst = imagecreatetruecolor($dst_w, $dst_h);
+    } else {
+        $dst = imagecreatetruecolor($dst_w, $dst_h);
+
+        if($src_w < $dst_w) {
+            if($src_h >= $dst_h) {
+                $dst_x = round(($dst_w - $src_w) / 2);
+                $src_h = $dst_h;
+            } else {
+                $dst_x = round(($dst_w - $src_w) / 2);
+                $dst_y = round(($dst_h - $src_h) / 2);
+                $dst_w = $src_w;
+                $dst_h = $src_h;
+            }
+        } else {
+            if($src_h < $dst_h) {
+                $dst_y = round(($dst_h - $src_h) / 2);
+                $dst_h = $src_h;
+                $src_w = $dst_w;
+            }
+        }
+
+        $bgcolor = imagecolorallocate($dst, 255, 255, 255); // 배경색
+        imagefill($dst, 0, 0, $bgcolor);
+    }
+
+    imagecopyresampled($dst, $src, $dst_x, $dst_y, $src_x, $src_y, $dst_w, $dst_h, $src_w, $src_h);
+
+    // sharpen 적용
+    if($is_sharpen && $is_large) {
+        $val = explode('/', $um_value);
+        UnsharpMask($dst, $val[0], $val[1], $val[2]);
     }
 
-    //imagepng($dst, $thumb_file, 9); // 0 (no compression) ~ 9
     imagejpeg($dst, $thumb_file, 90);
     chmod($thumb_file, 0606); // 추후 삭제를 위하여 파일모드 변경
 
+    imagedestroy($dst);
+
     return basename($thumb_file);
 }
 
+function UnsharpMask($img, $amount, $radius, $threshold)    {
+
+/*
+출처 : http://vikjavev.no/computing/ump.php
+New:
+- In version 2.1 (February 26 2007) Tom Bishop has done some important speed enhancements.
+- From version 2 (July 17 2006) the script uses the imageconvolution function in PHP
+version >= 5.1, which improves the performance considerably.
+
+
+Unsharp masking is a traditional darkroom technique that has proven very suitable for
+digital imaging. The principle of unsharp masking is to create a blurred copy of the image
+and compare it to the underlying original. The difference in colour values
+between the two images is greatest for the pixels near sharp edges. When this
+difference is subtracted from the original image, the edges will be
+accentuated.
+
+The Amount parameter simply says how much of the effect you want. 100 is 'normal'.
+Radius is the radius of the blurring circle of the mask. 'Threshold' is the least
+difference in colour values that is allowed between the original and the mask. In practice
+this means that low-contrast areas of the picture are left unrendered whereas edges
+are treated normally. This is good for pictures of e.g. skin or blue skies.
+
+Any suggenstions for improvement of the algorithm, expecially regarding the speed
+and the roundoff errors in the Gaussian blur process, are welcome.
+
+*/
+
+////////////////////////////////////////////////////////////////////////////////////////////////
+////
+////                  Unsharp Mask for PHP - version 2.1.1
+////
+////    Unsharp mask algorithm by Torstein Hønsi 2003-07.
+////             thoensi_at_netcom_dot_no.
+////               Please leave this notice.
+////
+///////////////////////////////////////////////////////////////////////////////////////////////
+
+
+
+    // $img is an image that is already created within php using
+    // imgcreatetruecolor. No url! $img must be a truecolor image.
+
+    // Attempt to calibrate the parameters to Photoshop:
+    if ($amount > 500)    $amount = 500;
+    $amount = $amount * 0.016;
+    if ($radius > 50)    $radius = 50;
+    $radius = $radius * 2;
+    if ($threshold > 255)    $threshold = 255;
+
+    $radius = abs(round($radius));     // Only integers make sense.
+    if ($radius == 0) {
+        return $img; imagedestroy($img); break;        }
+    $w = imagesx($img); $h = imagesy($img);
+    $imgCanvas = imagecreatetruecolor($w, $h);
+    $imgBlur = imagecreatetruecolor($w, $h);
+
+
+    // Gaussian blur matrix:
+    //
+    //    1    2    1
+    //    2    4    2
+    //    1    2    1
+    //
+    //////////////////////////////////////////////////
+
+
+    if (function_exists('imageconvolution')) { // PHP >= 5.1
+            $matrix = array(
+            array( 1, 2, 1 ),
+            array( 2, 4, 2 ),
+            array( 1, 2, 1 )
+        );
+        $divisor = array_sum(array_map('array_sum', $matrix));
+        $offset = 0;
+
+        imagecopy ($imgBlur, $img, 0, 0, 0, 0, $w, $h);
+        imageconvolution($imgBlur, $matrix, $divisor, $offset);
+    }
+    else {
+
+    // Move copies of the image around one pixel at the time and merge them with weight
+    // according to the matrix. The same matrix is simply repeated for higher radii.
+        for ($i = 0; $i < $radius; $i++)    {
+            imagecopy ($imgBlur, $img, 0, 0, 1, 0, $w - 1, $h); // left
+            imagecopymerge ($imgBlur, $img, 1, 0, 0, 0, $w, $h, 50); // right
+            imagecopymerge ($imgBlur, $img, 0, 0, 0, 0, $w, $h, 50); // center
+            imagecopy ($imgCanvas, $imgBlur, 0, 0, 0, 0, $w, $h);
+
+            imagecopymerge ($imgBlur, $imgCanvas, 0, 0, 0, 1, $w, $h - 1, 33.33333 ); // up
+            imagecopymerge ($imgBlur, $imgCanvas, 0, 1, 0, 0, $w, $h, 25); // down
+        }
+    }
+
+    if($threshold>0){
+        // Calculate the difference between the blurred pixels and the original
+        // and set the pixels
+        for ($x = 0; $x < $w-1; $x++)    { // each row
+            for ($y = 0; $y < $h; $y++)    { // each pixel
+
+                $rgbOrig = ImageColorAt($img, $x, $y);
+                $rOrig = (($rgbOrig >> 16) & 0xFF);
+                $gOrig = (($rgbOrig >> 8) & 0xFF);
+                $bOrig = ($rgbOrig & 0xFF);
+
+                $rgbBlur = ImageColorAt($imgBlur, $x, $y);
+
+                $rBlur = (($rgbBlur >> 16) & 0xFF);
+                $gBlur = (($rgbBlur >> 8) & 0xFF);
+                $bBlur = ($rgbBlur & 0xFF);
+
+                // When the masked pixels differ less from the original
+                // than the threshold specifies, they are set to their original value.
+                $rNew = (abs($rOrig - $rBlur) >= $threshold)
+                    ? max(0, min(255, ($amount * ($rOrig - $rBlur)) + $rOrig))
+                    : $rOrig;
+                $gNew = (abs($gOrig - $gBlur) >= $threshold)
+                    ? max(0, min(255, ($amount * ($gOrig - $gBlur)) + $gOrig))
+                    : $gOrig;
+                $bNew = (abs($bOrig - $bBlur) >= $threshold)
+                    ? max(0, min(255, ($amount * ($bOrig - $bBlur)) + $bOrig))
+                    : $bOrig;
+
+
+
+                if (($rOrig != $rNew) || ($gOrig != $gNew) || ($bOrig != $bNew)) {
+                        $pixCol = ImageColorAllocate($img, $rNew, $gNew, $bNew);
+                        ImageSetPixel($img, $x, $y, $pixCol);
+                    }
+            }
+        }
+    }
+    else{
+        for ($x = 0; $x < $w; $x++)    { // each row
+            for ($y = 0; $y < $h; $y++)    { // each pixel
+                $rgbOrig = ImageColorAt($img, $x, $y);
+                $rOrig = (($rgbOrig >> 16) & 0xFF);
+                $gOrig = (($rgbOrig >> 8) & 0xFF);
+                $bOrig = ($rgbOrig & 0xFF);
+
+                $rgbBlur = ImageColorAt($imgBlur, $x, $y);
+
+                $rBlur = (($rgbBlur >> 16) & 0xFF);
+                $gBlur = (($rgbBlur >> 8) & 0xFF);
+                $bBlur = ($rgbBlur & 0xFF);
+
+                $rNew = ($amount * ($rOrig - $rBlur)) + $rOrig;
+                    if($rNew>255){$rNew=255;}
+                    elseif($rNew<0){$rNew=0;}
+                $gNew = ($amount * ($gOrig - $gBlur)) + $gOrig;
+                    if($gNew>255){$gNew=255;}
+                    elseif($gNew<0){$gNew=0;}
+                $bNew = ($amount * ($bOrig - $bBlur)) + $bOrig;
+                    if($bNew>255){$bNew=255;}
+                    elseif($bNew<0){$bNew=0;}
+                $rgbNew = ($rNew << 16) + ($gNew <<8) + $bNew;
+                    ImageSetPixel($img, $x, $y, $rgbNew);
+            }
+        }
+    }
+    imagedestroy($imgCanvas);
+    imagedestroy($imgBlur);
+
+    return true;
+
+}
+
 function is_animated_gif($filename) {
     if(!($fh = @fopen($filename, 'rb')))
         return false;