Connect to host and get meta information.

def connect(self):
        """Connect to host and get meta information."""
        self.urlobj = getImageObject(self.url, self.referrer, self.session)
        content_type = unquote(self.urlobj.headers.get('content-type', 'application/octet-stream'))
        content_type = content_type.split(';', 1)[0]
        if '/' in content_type:
            maintype, subtype = content_type.split('/', 1)
        else:
            maintype = content_type
            subtype = None
        if maintype != 'image' and content_type not in ('application/octet-stream', 'application/x-shockwave-flash'):
            raise IOError('content type %r is not an image at %s' % (content_type, self.url))
        # Always use mime type for file extension if it is sane.
        if maintype == 'image':
            self.ext = '.' + subtype.replace('jpeg', 'jpg')
        self.contentLength = int(self.urlobj.headers.get('content-length', 0))
        out.debug(u'... filename = %r, ext = %r, contentLength = %d' % (self.filename, self.ext, self.contentLength))