code: public static String getRepresentationHintString(String repType, String repSize) {
          StringBuffer sb = new StringBuffer(repType);
          if(TYPE_JPG.equals(repType) || TYPE_PNG.equals(repType)) {
              if(TextUtils.isEmpty(repSize)) {
                  throw new InvalidParameterException("Size is not optional when creating representation hints for images");
              }
              sb.append("?" + BoxRepPropertiesMap.FIELD_PROPERTIES_DIMENSIONS + "=" + repSize);
          }
          return sb.toString();
      }
docs: Helper method to generate representation hint string
  @param repType the type of representation
  @param repSize the size of representation, used for image types. (please refer to dimension string
  @return string that can be used on server requests hinting the type of representation to return