function hideAll(objList) {

  for (var i = 0; i < objList.length; i++) {
    objList[i].style.display = 'none';
  }
}

function createBigImg(parentDiv, bigImgId, bigImgUrl) {

  var newBigImg = document.createElement('img');
  newBigImg.id = bigImgId;
  newBigImg.src = bigImgUrl;
  parentDiv.appendChild(newBigImg);
}

function displayBig(imgIndex, bigImgUrl) {

  var bigImgId = 'bigImg' + imgIndex;
  var bigImgDisp = document.getElementById('bigImgDisp');
  //bigImgDisp.style.width = '456px';
  //bigImgDisp.style.height = '342px';
  var imagesy = bigImgDisp.getElementsByTagName("img");
  hideAll(imagesy);
  if (!document.getElementById(bigImgId)) {createBigImg(bigImgDisp, bigImgId, bigImgUrl);}
  var bigImgToShow = document.getElementById(bigImgId);
  bigImgToShow.style.display='block';
}