PImage[] imgs;
int imgNo1;
int imgNo2;

void setup() 
{
  //Size of each square * 4 (1 initial, 4 after that)
  size(700, 700);
  String server = "http://doc.gold.ac.uk/~mas01mjy/itp2015/ex2/";
  String[] files = new String[16];
  for (int i=0; i<files.length; i++) 
  {
    files[i] = server + "image"+i+".png";
  }

  imgs = new PImage[files.length];  

  for (int i=0; i<files.length; i++) 
  {
    imgs[i] = loadImage(files[i]);
  }

  //imgs[3] = loadImage("http://cdn.cutestpaw.com/wp-content/uploads/2012/06/l-Monkey-munchies.jpeg");
}

void draw()
{
  int y = 0;
  int x = 0;
  for (int i = 0; i < imgs.length; i++)
  {
    image(imgs[i], x, y);
    imgs[i].resize(175, 175);
    if (mouseOver(x, y))
    {
      imgNo1 = i;
      println(imgNo1);
    }
    //Resized this so that each square is drawn at x + new width
    x += 175;
    if (i % 4 == 3)
    {
      //Adapted this to the new tile size
      y += 175;
      x = 0;
    }
  }
}

boolean mouseOver (float x, float y)
{
  if (mousePressed && (mouseX > x) && (mouseX < x + 175) && (mouseY > y) && (mouseY < y + 175))
  {
    return true;
  } 
  else
  {
    return false;
  }
}