add_file with image/gif file

[habdulkafi]

So, I'm trying to upload a gif to a form with mechanize. My code looks like:

sys.setdefaultencoding('UTF8') ## get similar errors without this
browser.open(url)
browser.select_form(nr=0)
browser.add_file(open('a.gif','rb'), name='file1', content_type='image/gif', filename='a.gif')
browser.submit()

The error I'm getting is:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_mechanize.py", line 541, in submit
    return self.open(self.click(*args, **kwds))
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_mechanize.py", line 203, in open
    return self._mech_open(url, data, timeout=timeout)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_mechanize.py", line 230, in _mech_open
    response = UserAgentBase.open(self, request, data)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_opener.py", line 193, in open
    response = urlopen(self, req, data)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_urllib2_fork.py", line 344, in _open
    '_open', req)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_urllib2_fork.py", line 332, in _call_chain
    result = func(*args)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_urllib2_fork.py", line 1170, in https_open
    return self.do_open(conn_factory, req)
  File "/usr/local/lib/python2.7/dist-packages/mechanize/_urllib2_fork.py", line 1115, in do_open
    h.request(req.get_method(), req.get_selector(), req.data, headers)
  File "/usr/lib/python2.7/httplib.py", line 979, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python2.7/httplib.py", line 1013, in _send_request
    self.endheaders(body)
  File "/usr/lib/python2.7/httplib.py", line 975, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python2.7/httplib.py", line 833, in _send_output
    msg += message_body
  File "/usr/lib/python2.7/encodings/utf_8.py", line 16, in decode
    return codecs.utf_8_decode(input, errors, True)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xff in position 837: invalid start byte

I'm unsure really what is going on here. Could this be related to this or this? Those bugs seem quite old, but also unfixed as of now. Am I right in connecting these two and thinking this bug isn't fixed? Thanks in advance