docs: public static String getImageFileFormat(File imageFile) {
          String imageFileName = imageFile.getName();
          String imageFormat = imageFileName.substring(imageFileName.lastIndexOf('.') + 1);
          if (imageFormat.matches("(pbm|pgm|ppm)")) {
              imageFormat = "pnm";
          } else if (imageFormat.matches("(jp2|j2k|jpf|jpx|jpm)")) {
              imageFormat = "jpeg2000";
          }
          return imageFormat;
      }