diff --git a/include/watermark_runtime.inc.php b/include/watermark_runtime.inc.php
new file mode 100644
index 0000000..eba8966
--- /dev/null
+++ b/include/watermark_runtime.inc.php
@@ -0,0 +1,97 @@
+<?php
+if (!defined('PHPWG_ROOT_PATH'))
+{
+  die('Hacking attempt!');
+}
+
+require_once(BRATONIEN_TOOLS_PATH . 'include/database.class.php');
+require_once(BRATONIEN_TOOLS_PATH . 'include/watermark_engine.inc.php');
+require_once(BRATONIEN_TOOLS_PATH . 'tools/watermark_settings.inc.php');
+require_once(BRATONIEN_TOOLS_PATH . 'tools/watermark_profiles.inc.php');
+require_once(BRATONIEN_TOOLS_PATH . 'tools/album_rules.inc.php');
+
+function bratonien_tools_runtime_category_id()
+{
+  global $page;
+
+  if (!empty($page['category']['id']))
+  {
+    return (int)$page['category']['id'];
+  }
+
+  if (!empty($page['category']) && is_numeric($page['category']))
+  {
+    return (int)$page['category'];
+  }
+
+  return 0;
+}
+
+function bratonien_tools_runtime_effective_rule($category_id)
+{
+  static $categories = null;
+  static $rules = null;
+  static $defaults = null;
+
+  if ($categories === null)
+  {
+    $categories = bratonien_tools_get_category_tree();
+    $rules = bratonien_tools_get_album_rules();
+    $defaults = bratonien_tools_get_watermark_defaults();
+  }
+
+  if ((int)$category_id <= 0)
+  {
+    if (empty($defaults['public_profile']))
+    {
+      return array('mode'=>'disabled','profile_id'=>null,'source'=>'global');
+    }
+    return array('mode'=>'profile','profile_id'=>(int)$defaults['public_profile'],'source'=>'global');
+  }
+
+  return bratonien_tools_resolve_album_rule((int)$category_id, $categories, $rules, $defaults);
+}
+
+function bratonien_tools_runtime_sign($rel_url, $profile_id)
+{
+  global $conf;
+  $key = !empty($conf['secret_key']) ? $conf['secret_key'] : $conf['db_password'];
+  return hash_hmac('sha256', $profile_id.'|'.$rel_url, $key);
+}
+
+function bratonien_tools_runtime_b64url_encode($value)
+{
+  return rtrim(strtr(base64_encode($value), '+/', '-_'), '=');
+}
+
+function bratonien_tools_filter_derivative_url($url, $params, $src_image, $rel_url)
+{
+  if (!bratonien_tools_watermark_engine_enabled())
+  {
+    return $url;
+  }
+
+  $rule = bratonien_tools_runtime_effective_rule(bratonien_tools_runtime_category_id());
+  if ($rule['mode'] !== 'profile' || empty($rule['profile_id']))
+  {
+    return $url;
+  }
+
+  $profile = bratonien_tools_get_watermark_profile((int)$rule['profile_id']);
+  if (!$profile || empty($profile['watermark_file']))
+  {
+    return $url;
+  }
+
+  $watermark_path = PHPWG_ROOT_PATH.PWG_LOCAL_DIR.'watermarks/'.$profile['watermark_file'];
+  if (!is_file($watermark_path))
+  {
+    return $url;
+  }
+
+  $profile_id = (int)$profile['id'];
+  $signature = bratonien_tools_runtime_sign($rel_url, $profile_id);
+
+  return get_root_url().'plugins/'.BRATONIEN_TOOLS_ID.'/watermark.php?p='.$profile_id.'&u='.
+    rawurlencode(bratonien_tools_runtime_b64url_encode($rel_url)).'&s='.$signature;
+}