var mpPref = Components.classes["@mozilla.org/preferences-service;1"].getService(Components.interfaces.nsIPrefBranch);

function MSNP_OptionsInit() {
  //load current. Note: we need to use the var "elem" here
  var elem = document.getElementById("mp.showMSNP");
  elem.checked = mpPref.getBoolPref(elem.getAttribute("prefstring"));
  
  elem = document.getElementById("mp.insertImages");
  elem.checked = mpPref.getBoolPref(elem.getAttribute("prefstring"));  
}

function MSNP_OptionsSave() {
  // save current. We may not need to use elem, but we will just in case
  try {
    var elem = document.getElementById("mp.showMSNP");
    mpPref.setBoolPref(elem.getAttribute("prefstring"), elem.checked);
    
    elem = document.getElementById("mp.insertImages");
    mpPref.setBoolPref(elem.getAttribute("prefstring"), elem.checked);

    //reinit 
    try {
      opener.MP_PREFS = null;
      opener.getPrefs();
      opener.setIcon(elem.checked);
      opener.reloadLocation();
    }
    catch (ex) {
      opener.opener.MP_PREFS = null;
      opener.opener.getPrefs();
      opener.opener.setIcon(elem.checked);
      opener.opener.reloadLocation();
    }    
  }
  catch (e) {alert(e);}
  return true;
}