// image static
PImage colorbars;
int x;

void setup(){
  size(320,240);
  colorbars = loadImage("colorbars.jpg");
}

void draw(){
  //image(colorbars, 0,0);
  if(mouseX > 0){
    x = mouseX;
  } else {
    x = 1;
  }
  loadPixels();
  for(int i=0; i<width*height; i++){
    pixels[i] = colorbars.pixels[i/x];
  }
  updatePixels();
}