Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/gwibber/microblog/dispatcher.py", line 913, in handle_notify_item
    util.notify(sender_name, notify_text, image, 2000)
  File "/usr/lib/python2.7/dist-packages/gwibber/microblog/util/__init__.py", line 231, in notify
    pixbuf = GdkPixbuf.Pixbuf.new_from_file_at_size(icon, iconsize, iconsize)
  File "/usr/lib/python2.7/dist-packages/gi/types.py", line 72, in constructor
    return info.invoke(cls, *args, **kwargs)
GError: Unrecognized image file format