public Boolean isJettyBaseimage() throws InvalidImageReferenceException {
    if (from != null) {
      ImageReference baseImageReference = ImageReference.parse(from);
      return baseImageReference.getRegistry().equals("registry-1.docker.io")
          && baseImageReference.getRepository().equals("library/jetty");
    }
    return true;
  }
Returns {@code true} if the user-specified base image is jetty or if a custom base image is not
specified.

@return a boolean
@throws InvalidImageReferenceException if image reference is invalid
jib-cli/src/main/java/com/google/cloud/tools/jib/cli/CommonContainerConfigCliOptions.java