Basic exponentially reducing circle image processing for Processing

CircleImage.pde

PImage imgOriginal, imgNew;
color c;

void setup() {
  imgOriginal = loadImage("IMG_6319.jpg"); // load image here
  hint(DISABLE_DEPTH_TEST);
  blendMode(MULTIPLY);
  
  imgNew = new PImage(1200,600);
  imgNew.copy(imgOriginal,0,0,imgOriginal.width,imgOriginal.height,0,0,1200,600); // stretch original image to size

  size(imgNew.width,imgNew.height);

  background(255);
  
  for (int i=0;i<5;i++) {
  
    int sz = (int)(80/pow(2,i));
    
    for (int y=0;y<height+40;y+=40) {
      for (int x=0;x<width+40;x+=40) {
        color c1 = imgNew.get(x-sz,y);
        color c2 = imgNew.get(x+sz,y);
        color c3 = imgNew.get(x,y-sz);
        color c4 = imgNew.get(x,y+sz);
        
        // use average if not the smallest dot, in which case use the color at the center point
        if (i != 4) {
          c = color((red(c1)+red(c2)+red(c3)+red(c4))/4,(green(c1)+green(c2)+green(c3)+green(c4))/4,(blue(c1)+blue(c2)+blue(c3)+blue(c4))/4);
        } else {
          c = imgNew.get(x,y);
        }
        
        fill(c,200);
        noStroke();
        ellipse(20+x,20+y,sz,sz);
      }
    }
  }
}

void draw() {
}

void keyPressed() {
  if (key == ' ') {
    save("image_"+millis()+".png");
  }
}