function imgButtonPressed(event){
  /// get form ///
  var curform = event.srcElement;
  while(curform.tagName != "FORM") {
    curform = curform.parentNode;
  }

  /// create hidden input with values of image submit ///  
  var hid = document.createElement("input");
  hid.type = "hidden";

  hid.name = event.srcElement.name;
  hid.value = event.srcElement.value;

  curform.appendChild(hid)
}
onload = function() {
  inputs = document.getElementsByTagName("input");
  if (inputs[0].attachEvent) {
    for (a = 0; a < inputs.length; a++) {
      if (inputs[a].type == "image") {
        inputs[a].attachEvent('onclick', imgButtonPressed);
      }
    }
  }
}