code: public String getOriginalUrl() throws FlickrException {
          if (originalSize == null) {
              if (originalFormat != null) {
                  return getOriginalBaseImageUrl() + "_o." + originalFormat;
              }
              return getOriginalBaseImageUrl() + DEFAULT_ORIGINAL_IMAGE_SUFFIX;
          } else {
              return originalSize.getSource();
          }
      }
docs: Get the original image URL.
  
  @return The original image URL