code: public INDArray toBgr(File file) {
          try {
              BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));
              INDArray ret = toBgr(bis);
              bis.close();
              return ret;
          } catch (IOException e) {
              throw new RuntimeException(e);
          }
      }
docs: Convert an input stream to an bgr spectrum image
  
  @param file the file to convert
  @return the input stream to convert