Index: branches/5.2.x/core/install/upgrades.php
===================================================================
diff -u -N -r15608 -r16247
--- branches/5.2.x/core/install/upgrades.php	(.../upgrades.php)	(revision 15608)
+++ branches/5.2.x/core/install/upgrades.php	(.../upgrades.php)	(revision 16247)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: upgrades.php 15608 2012-11-06 17:21:28Z alex $
+* @version	$Id: upgrades.php 16247 2015-09-02 20:48:06Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -2338,4 +2338,43 @@
 				$this->Conn->doUpdate($fields_hash, TABLE_PREFIX . 'Users', 'PortalUserId = ' . $user_id);
 			}
 		}
-	}
\ No newline at end of file
+
+		/**
+		 * Update to 5.2.2-B1
+		 *
+		 * @param string $mode when called mode {before, after)
+		 */
+		public function Upgrade_5_2_2_B1($mode)
+		{
+			if ( $mode != 'after' ) {
+				return;
+			}
+
+			$this->deleteThumbnails();
+		}
+
+		/**
+		 * Deletes folders, containing thumbnails recursively.
+		 *
+		 * @param string $folder Folder.
+		 *
+		 * @return void
+		 */
+		protected function deleteThumbnails($folder = WRITEABLE)
+		{
+			foreach ( glob($folder . '/*', GLOB_ONLYDIR) as $sub_folder ) {
+				if ( $sub_folder === WRITEABLE . '/cache' ) {
+					continue;
+				}
+
+				if ( basename($sub_folder) === 'resized' ) {
+					$files = glob($sub_folder . '/*');
+					array_map('unlink', $files);
+					rmdir($sub_folder);
+				}
+				else {
+					$this->deleteThumbnails($sub_folder);
+				}
+			}
+		}
+	}