urllib.urlretrieve returns silently even if the file doesn't exist on the remote http server, it just saves a html page to the named file. For example: urllib.urlretrieve('http://google.com/abc.jpg', 'abc.jpg') just returns silently, even if abc.jpg doesn't exist on google.com server, the generated abc.jpg is not a valid jpg file, it's actually a html page . I guess the returned headers (a httplib
