diff --git a/runtime/lib/build-webdav-derivatives.php b/runtime/lib/build-webdav-derivatives.php
new file mode 100644
index 0000000..8473705
--- /dev/null
+++ b/runtime/lib/build-webdav-derivatives.php
@@ -0,0 +1,97 @@
+#!/usr/bin/env php
+<?php
+if (PHP_SAPI !== 'cli')
+{
+  fwrite(STDERR, "CLI only\n");
+  exit(1);
+}
+
+$options = getopt('', array('piwigo-root:', 'connection-id:'));
+$piwigo_root = rtrim((string)($options['piwigo-root'] ?? ''), '/');
+$connection_id = (int)($options['connection-id'] ?? 0);
+if ($piwigo_root === '' || $connection_id < 1)
+{
+  fwrite(STDERR, "Parameter --piwigo-root und --connection-id werden benoetigt.\n");
+  exit(1);
+}
+if (!is_dir($piwigo_root))
+{
+  fwrite(STDERR, "Piwigo-Root wurde nicht gefunden.\n");
+  exit(1);
+}
+
+define('PHPWG_ROOT_PATH', $piwigo_root.'/');
+$_SERVER['REMOTE_ADDR'] = '127.0.0.1';
+$_SERVER['SERVER_ADDR'] = '127.0.0.1';
+$_SERVER['SERVER_NAME'] = 'localhost';
+$_SERVER['HTTP_HOST'] = 'localhost';
+$_SERVER['SERVER_PORT'] = '80';
+$_SERVER['REQUEST_METHOD'] = 'GET';
+$_SERVER['REQUEST_URI'] = '/';
+$_SERVER['SCRIPT_NAME'] = '/plugins/bratonien_tools/runtime/lib/build-webdav-derivatives.php';
+$_SERVER['PHP_SELF'] = $_SERVER['SCRIPT_NAME'];
+$_SERVER['QUERY_STRING'] = '';
+$_SERVER['HTTP_USER_AGENT'] = 'Bratonien-WebDAV-Derivative-Builder/0.9.5.20';
+$_SERVER['HTTPS'] = 'off';
+
+require_once(PHPWG_ROOT_PATH.'include/common.inc.php');
+require_once(PHPWG_ROOT_PATH.'include/derivative.inc.php');
+require_once(PHPWG_ROOT_PATH.'admin/include/image.class.php');
+
+if (!function_exists('bratonien_tools_webdav_image_source_info') || !function_exists('bratonien_tools_webdav_generate_derivative'))
+{
+  fwrite(STDERR, "Bratonien WebDAV-Bildruntime ist nicht aktiv.\n");
+  exit(1);
+}
+
+try
+{
+  $variants = bratonien_tools_webdav_derivative_variants();
+  if (!$variants)
+  {
+    throw new RuntimeException('Keine Piwigo-Derivate konfiguriert.');
+  }
+
+  $images = 0;
+  $generated = 0;
+  $errors = 0;
+
+  $result = pwg_query('SELECT * FROM '.IMAGES_TABLE.' ORDER BY id');
+  while ($row = pwg_db_fetch_assoc($result))
+  {
+    $image_id = (int)$row['id'];
+    $info = bratonien_tools_webdav_image_source_info($image_id);
+    if (!$info || (int)$info['connection_id'] !== $connection_id) continue;
+
+    $images++;
+    $src = new SrcImage($row);
+    foreach ($variants as $variant_name => $params)
+    {
+      try
+      {
+        if (bratonien_tools_webdav_generate_derivative($params, $src))
+        {
+          $generated++;
+        }
+        else
+        {
+          $errors++;
+          fwrite(STDERR, 'Bild #'.$image_id.' '.$variant_name.": Derivat konnte nicht erzeugt werden.\n");
+        }
+      }
+      catch (Throwable $e)
+      {
+        $errors++;
+        fwrite(STDERR, 'Bild #'.$image_id.' '.$variant_name.': '.$e->getMessage()."\n");
+      }
+    }
+  }
+
+  echo 'WebDAV-Derivate: bilder='.$images.' varianten='.count($variants).' bereit='.$generated.' fehler='.$errors."\n";
+  exit($errors > 0 ? 1 : 0);
+}
+catch (Throwable $e)
+{
+  fwrite(STDERR, 'WebDAV-Derivate: '.$e->getMessage()."\n");
+  exit(1);
+}