function toggleVisibility(idImg, idDiv) {
  var div = document.getElementById(idDiv);
  var img = document.getElementById(idImg);
  if (div.style.display === "none") {
    div.style.display = "block";
    img.src = "res/hide.png";
  } else {
    div.style.display = "none";
    img.src = "res/show.png";
  }
}