i have been create grayscale and reset button in setup procedure,

then i have procedure RGB2Grayscale, that working good.

then the problem is with my reset procedure,

public void Reset() { 
  for (int j = 0; j < img.height; j++) {
    for (int i = 0; i < img.width; i++) {
      color c = img.get(i, j);
      float r = red(c);
      float g = green(c);
      float b = blue(c);
      color grayscale2 = color(r, g, b);
      img.set(i, j, grayscale2);
    }
  }
}

after i click RGB2Grayscale button and the image be grayscale. then i click Reset button, then no chage with my image, maybe because Reset procedure read pixel value of image, after grayscale.

if i want to save pixel value automatically after image loaded, so when image pixel have chaged, i have the backup the original pixel value.

can i do that??