PImage img;
float py;
int frames = 72;

void setup() {
  img = loadImage("http://media-cache-ak0.pinimg.com/736x/f4/34/85/f43485adbf64b6f3a0b449820aec3703.jpg");
  size(img.width, img.height);
  image(img, 0, 0);
  py = -height/3;
}  

void draw() {
  loadPixels();
  img.loadPixels();
  float scope = height*.4;
  for (int x=0; x<width; x++) {
    for (int y=0; y<height; y++) {
      int loc = x+y*width;
      float r = red(img.pixels[loc]);
      float g = green(img.pixels[loc]);
      float b = blue(img.pixels[loc]);
      float d = dist(width/2, py, x, y);
      float factor = map(d, 0, scope, 1, 0);
      pixels[loc]=color(r*factor, g*factor, b*factor);
    }
  }
  updatePixels();
  py += (height+2*scope)/frames;
  saveFrame("image-###.gif");
  if (frameCount==frames) noLoop();
}