code: public static String buildPath(String journalId, long txid,
        NamespaceInfo nsInfo, boolean throttle) {
      StringBuilder path = new StringBuilder("/getImage?getimage=1&");
      try {
        path.append(JOURNAL_ID_PARAM).append("=")
            .append(URLEncoder.encode(journalId, "UTF-8"));
        path.append("&" + TXID_PARAM).append("=")
            .append(txid);
        path.append("&" + THROTTLE_PARAM).append("=")
            .append(throttle);
        path.append("&" + STORAGEINFO_PARAM).append("=")
            .append(URLEncoder.encode(nsInfo.toColonSeparatedString(), "UTF-8"));
      } catch (UnsupportedEncodingException e) {
        // Never get here -- everyone supports UTF-8
        throw new RuntimeException(e);
      }
      return path.toString();
    }
docs: Build path to fetch image at given txid for the given journal.
  This path does not contain address.