I saw the different answers to this kind of question but i didn't found any answer for my problem:

When I run this sketch it works but after a time it takes me this "error":

PImage img;
int x, y;
float r, g, b;

void setup(){
  size(200,200);
  img = loadImage("sunflower.jpg");
}
void draw(){
  loadPixels();
  img.loadPixels();
  int loc = x + y*width;
  r = red(img.pixels[loc]);
  g = green(img.pixels[loc]);
  b = blue(img.pixels[loc]);
  pixels[loc] = color(r,g,b);

x++;

if (x>width){
  y++;}
if (y>height){
  y=0;
}
background(pixels[loc]);
}

Can anybody help me?
Thanks!

Agustín