Brightsize

PImage myImage;
color col;
float sw, br, incr;

void setup() {
  background(0);
  colorMode(HSB, 100);
  myImage = loadImage("pal1.gif");
  size(myImage.width, myImage.height);
  myImage.loadPixels();
  incr = 5;
}

void draw() {
background(0);
  for (int x = 0;  x<width; x += incr) {
    for (int y = 0; y < height; y += incr) {
      col = myImage.pixels[y*width+x];
      sw = map(brightness(myImage.get(x, y)), 0, 100, 1, 20) ;
      br = brightness(myImage.get(x, y));
      stroke(myImage.get(x, y), 150);
      strokeWeight(sw);
      point(x,y);
    }
  }
}

void keyPressed() {
  save(random(123)+".png");
}