function closePopupImage() {
  document.getElementById("popup-image").style.display = "none";
}

function showPopupImage() {
  if(popupImageShow) {
      var content = '<div id="pi-graybg"></div><a';
      if(popupLink != '') content += ' style="padding-bottom:0;"';
      content += ' href="javascript:void;" onclick="closePopupImage();" title="zavřít upoutávku"><span>kliknutím sem upoutávku zavřete</span>';
      if(popupLink != '') content += '</a><a style="padding-top:0;" href="' + popupLink + '">';
      content += '<img src="' + popupImageUrl + '" alt="upoutávka" /></a>';
    document.getElementById("popup-image").innerHTML = content;
    document.getElementById("popup-image").style.display = "block";
  }
}