void keyPressed()
{
  switch(keyCode) {
    case RIGHT:
      activeImg++;
      break;
    case LEFT:
      activeImg--;
      break;
  }
  if(activeTool < 0) {
    activeTool = toolNames.length - 1;
  } else if (activeTool > toolNames.length - 1) {
    activeTool = 0; 
  }
  if(activeImg < 0) {
    activeImg = img.length - 1;
  } else if (activeImg > img.length - 1) {
    activeImg = 0;
  }
  if(key == 'n') {
    loadBackgroundImages();
  }
}