Index: branches/5.3.x/core/units/helpers/image_helper.php
===================================================================
diff -u -N -r15902 -r15975
--- branches/5.3.x/core/units/helpers/image_helper.php	(.../image_helper.php)	(revision 15902)
+++ branches/5.3.x/core/units/helpers/image_helper.php	(.../image_helper.php)	(revision 15975)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: image_helper.php 15902 2013-07-12 15:37:15Z alex $
+* @version	$Id: image_helper.php 15975 2013-10-03 13:20:13Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -64,6 +64,11 @@
 				} elseif (preg_match('/^default:(.*)$/', $format_part, $regs)) {
 					$res['default'] = FULL_PATH.THEMES_PATH.'/'.$regs[1];
 				}
+				elseif ( preg_match('/^filter:(.*)$/', $format_part, $regs) ) {
+					$format_part_params = explode('|', $regs[1]);
+					$res['filter_type'] = array_shift($format_part_params);
+					$res['filter_params'] = $format_part_params;
+				}
 			}
 
 			return $res;
@@ -117,7 +122,7 @@
 				}
 
 				$src_path = dirname($src_image);
-				$transform_keys = Array ('crop_x', 'crop_y', 'fill', 'wm_filename');
+				$transform_keys = Array ('crop_x', 'crop_y', 'fill', 'wm_filename', 'filter_type');
 
 				if ($needs_resize || array_intersect(array_keys($params), $transform_keys)) {
 					// resize required OR watermarking required -> change resulting image name !
@@ -224,6 +229,9 @@
 						return @$write_function($dst_image_rs, $params['dst_image']);
 					}
 
+					// 4. apply filter
+					$this->applyFilter($dst_image_rs, $params);
+
 					return @$write_function($dst_image_rs, $params['dst_image'], $write_function == 'imagepng' ? 0 : 100);
 				}
 			}
@@ -417,6 +425,36 @@
 		}
 
 		/**
+		 * Applies filter to an image.
+		 *
+		 * @param resource $src_image_rs Source image.
+		 * @param array $params Parameters.
+		 *
+		 * @return boolean
+		 * @access protected
+		 * @throws InvalidArgumentException When unknown filter type given.
+		 * @link   http://php.net/manual/en/function.imagefilter.php
+		 */
+		protected function applyFilter(&$src_image_rs, array $params)
+		{
+			if ( !array_key_exists('filter_type', $params) ) {
+				return true;
+			}
+
+			$filter_type = strtoupper($params['filter_type']);
+			$filter_params = (array)$params['filter_params'];
+
+			if ( !defined('IMG_FILTER_' . $filter_type) ) {
+				throw new InvalidArgumentException(sprintf('Unknown filter type "%s"', $filter_type));
+			}
+
+			array_unshift($filter_params, constant('IMG_FILTER_' . $filter_type));
+			array_unshift($filter_params, $src_image_rs);
+
+			return call_user_func_array('imagefilter', $filter_params);
+		}
+
+		/**
 		 * Returns destination image size without actual resizing (useful for <img .../> HTML tag)
 		 *
 		 * @param string $src_image full path to source image (already existing)