diff --git a/include/watermark_base.inc.php b/include/watermark_base.inc.php
new file mode 100644
index 0000000..46a6a45
--- /dev/null
+++ b/include/watermark_base.inc.php
@@ -0,0 +1,102 @@
+<?php
+if (!defined('PHPWG_ROOT_PATH'))
+{
+  die('Hacking attempt!');
+}
+
+function bratonien_tools_load_derivative_params()
+{
+  if (!class_exists('ImageStdParams'))
+  {
+    require_once(PHPWG_ROOT_PATH . 'include/derivative_std_params.inc.php');
+  }
+}
+
+function bratonien_tools_watermark_params_to_array($watermark)
+{
+  return array(
+    'file' => (string)($watermark->file ?? ''),
+    'xpos' => (int)($watermark->xpos ?? 50),
+    'ypos' => (int)($watermark->ypos ?? 50),
+    'xrepeat' => (int)($watermark->xrepeat ?? 0),
+    'yrepeat' => (int)($watermark->yrepeat ?? 0),
+    'opacity' => (int)($watermark->opacity ?? 100),
+    'minw' => isset($watermark->min_size[0]) ? (int)$watermark->min_size[0] : 500,
+    'minh' => isset($watermark->min_size[1]) ? (int)$watermark->min_size[1] : 500,
+  );
+}
+
+function bratonien_tools_array_to_watermark_params(array $data)
+{
+  bratonien_tools_load_derivative_params();
+
+  $watermark = new WatermarkParams();
+  $watermark->file = (string)($data['file'] ?? '');
+  $watermark->xpos = (int)($data['xpos'] ?? 50);
+  $watermark->ypos = (int)($data['ypos'] ?? 50);
+  $watermark->xrepeat = (int)($data['xrepeat'] ?? 0);
+  $watermark->yrepeat = (int)($data['yrepeat'] ?? 0);
+  $watermark->opacity = (int)($data['opacity'] ?? 100);
+  $watermark->min_size = array(
+    (int)($data['minw'] ?? 500),
+    (int)($data['minh'] ?? 500),
+  );
+  return $watermark;
+}
+
+function bratonien_tools_default_base_watermark_config()
+{
+  return array(
+    'file' => '',
+    'xpos' => 90,
+    'ypos' => 90,
+    'xrepeat' => 0,
+    'yrepeat' => 0,
+    'opacity' => 35,
+    'minw' => 10,
+    'minh' => 10,
+    'scale_percent' => 100.0,
+  );
+}
+
+function bratonien_tools_save_base_watermark_config(array $config)
+{
+  if (!function_exists('conf_update_param'))
+  {
+    throw new RuntimeException('Piwigo-Konfiguration ist nicht verfuegbar.');
+  }
+
+  $config = array_merge(bratonien_tools_default_base_watermark_config(), $config);
+  $config['scale_percent'] = max(1.0, min(1000.0, (float)$config['scale_percent']));
+  conf_update_param('bratonien_watermark_base', json_encode($config));
+  // Keep the old single-value setting in sync for compatibility with 0.3.0.
+  conf_update_param('bratonien_watermark_base_scale_percent', (string)$config['scale_percent']);
+}
+
+function bratonien_tools_get_base_watermark_config()
+{
+  $default = bratonien_tools_default_base_watermark_config();
+  if (!function_exists('conf_get_param'))
+  {
+    return $default;
+  }
+
+  $stored = conf_get_param('bratonien_watermark_base', null);
+  if (!empty($stored))
+  {
+    $decoded = json_decode($stored, true);
+    if (is_array($decoded))
+    {
+      return array_merge($default, $decoded);
+    }
+  }
+
+  // Migration from the previous implementation: before 0.3.1 the base
+  // watermark was stored directly in Piwigo's native watermark parameters.
+  bratonien_tools_load_derivative_params();
+  $native = bratonien_tools_watermark_params_to_array(ImageStdParams::get_watermark());
+  $native['scale_percent'] = (float)conf_get_param('bratonien_watermark_base_scale_percent', 100);
+  $config = array_merge($default, $native);
+  bratonien_tools_save_base_watermark_config($config);
+  return $config;
+}