def send_image_url(url, opt, refer, &callback)
      begin
        opt = {} if opt.nil?
        http = EM::HttpRequest.new(url, :connect_timeout => 2, :inactivity_timeout => 5).get opt
        file = Tempfile.new(['image', 'jpg'])
        http.stream { |chunk|
          file.write(chunk)
        }
        http.callback {
          file.close
          type = FastImage.type(file.path)
          if %i(jpeg png gif).include?(type)
            send_image(file.path, refer, &callback)
          else
            fail_back(&callback)
          end
        }
      rescue Exception => e
        logger.error("An error occurred during the image downloading: #{e.inspect} #{e.backtrace}")
        fail_back(&callback)
      end
    end
def send_image_url(url, opt, refer, &callback)
      begin
        opt = {} if opt.nil?
        http = EM::HttpRequest.new(url, :connect_timeout => 2, :inactivity_timeout => 5).get opt
        file = Tempfile.new(['image', 'jpg'])
        http.stream { |chunk|
          file.write(chunk)
        }
        http.callback {
          file.close
          type = FastImage.type(file.path)
          if %i(jpeg png gif).include?(type)
            send_image(file.path, refer, &callback)
          else
            fail_back(&callback)
          end
        }
      rescue Exception => e
        logger.error("An error occurred during the image downloading: #{e.inspect} #{e.backtrace}")
        fail_back(&callback)
      end
    end
Send an image with given url, not implemen

 @param [String] url The URL of the image you want to send
 @param [TelegramMessage] refer referral of the method call
 @param [Block] callback Callback block that will be called when finished
 @since [0.1.1]