    static CImg<T> get_load_png(const char *const filename, unsigned int *const bits_per_value=0) {
      return CImg<T>().load_png(filename,bits_per_value);
    }
    static CImg<T> get_load_png(const char *const filename, unsigned int *const bits_per_value=0) {
      return CImg<T>().load_png(filename,bits_per_value);
    }