-        thumbnail = self._html_search_regex(
-            r'flashvars\.imageUrl\s*=\s*"([^"]+)"', webpage, 'description', fatal=False, default=None)
-        if thumbnail:
-            thumbnail = 'http://www.vporn.com' + thumbnail
+        thumbnail = urljoin('http://www.vporn.com', self._html_search_regex(
+            r'flashvars\.imageUrl\s*=\s*"([^"]+)"', webpage, 'description',
+            default=None))