diff --git a/Configuration/ElFinderConfigurationReader.php b/Configuration/ElFinderConfigurationReader.php
index 994eddb..d572693 100644
--- a/Configuration/ElFinderConfigurationReader.php
+++ b/Configuration/ElFinderConfigurationReader.php
@@ -102,7 +102,7 @@ public function getConfiguration($instance)
                 'imgLib'            => $parameter['img_lib'],
                 'tmbPath'           => $parameter['tmb_path'],
                 'tmbPathMode'       => $parameter['tmb_path_mode'],
-                'tmbUrl'            => $parameter['tmb_url'],
+                'tmbURL'            => $parameter['tmb_url'],
                 'tmbSize'           => $parameter['tmb_size'],
                 'tmbCrop'           => $parameter['tmb_crop'],
                 'tmbBgColor'        => $parameter['tmb_bg_color'],
diff --git a/Tests/Configuration/ElFinderConfigurationReaderTest.php b/Tests/Configuration/ElFinderConfigurationReaderTest.php
index eb43aac..234eb09 100644
--- a/Tests/Configuration/ElFinderConfigurationReaderTest.php
+++ b/Tests/Configuration/ElFinderConfigurationReaderTest.php
@@ -152,4 +152,10 @@ public function testAccessVisible()
         $this->assertNull($this->reader->access('read', $visiblePath, 'dummy', 'dummy'));
         $this->assertNull($this->reader->access('write', $visiblePath, 'dummy', 'dummy'));
     }
+
+    public function testAccessTmbURLOpion()
+    {
+        $configuration = $this->reader->getConfiguration('default');
+        $this->assertArrayHasKey('tmbURL', $configuration['roots'][0]);
+    }
 }