def captcha_tag(*args)
      options = { :alt => 'captcha', :width => EasyCaptcha.image_width, :height => EasyCaptcha.image_height }
      options.merge! args.extract_options!
      image_tag(captcha_url(:i => Time.now.to_i), options)
    end
def captcha_tag(*args)
      options = { :alt => 'captcha', :width => EasyCaptcha.image_width, :height => EasyCaptcha.image_height }
      options.merge! args.extract_options!
      image_tag(captcha_url(:i => Time.now.to_i), options)
    end
generate an image_tag for captcha image