'Find CAPTCHA images.
:param fuzzable_request: A fuzzable_request instance that contains
(among other things) the URL to test.'

def crawl(self, fuzzable_request):

    (result, captchas) = self._identify_captchas(fuzzable_request)
    if result:
        for captcha in captchas:
            desc = ('Found    a    CAPTCHA    image    at:    "%s".' % captcha.img_src)
            response_ids = [response.id for response in captcha.http_responses]
            i = Info('Captcha    image    detected', desc, response_ids, self.get_name())
            i.set_uri(captcha.img_src)
            kb.kb.append(self, 'CAPTCHA', i)
            om.out.information(i.get_desc())
