Saving JPG to PNG using Save for the Web

Question

Morning
I came across Paul Riggott's script for saving PSD to PNG which I changed to JPG to PSD.
The only problem with this is that the file size in most cases is larger than the original.
Is there a way to do a save as for the web as well?
Here is the  original code:
#target photoshop
var imageFolder = Folder.selectDialog("Select top folder to process");
var folderList=[];
if (imageFolder != null)  {
processFolder(imageFolder);
folderList.unshift(imageFolder);
createPNGfromJPG(folderList);
function createPNGfromJPG(folderList){
for(var a in folderList){
  var fileList = folderList[a].getFiles ("*.jpg");
   for (var z in fileList){
    var file = fileList[z];
    open(file);
    var Name = fileList[z].name.replace(/\.[^\.]+$/, '');
    var saveFile = File(decodeURI(fileList[z].path+"/"+Name+".png"));
    SavePNG(saveFile);
    app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
function processFolder(folder) {
    var fileList = folder.getFiles()
     for (var i = 0; i < fileList.length; i++) {
        var file = fileList[i];
if (file instanceof Folder) {
  folderList.push(file); 
       processFolder(file);
function SavePNG(saveFile){
    pngSaveOptions = new PNGSaveOptions();
    pngSaveOptions.embedColorProfile = true;
    pngSaveOptions.formatOptions = FormatOptions.STANDARDBASELINE;
    pngSaveOptions.matte = MatteType.NONE;
    pngSaveOptions.quality = 1;
pngSaveOptions.PNG8 = false;
    pngSaveOptions.transparency = true;
activeDocument.saveAs(saveFile, pngSaveOptions, true, Extension.LOWERCASE);
Any help or support to head me in the right direction would be appreciated.
Iain

Answer 1

This uses "Fitimage"....
#target photoshop
var imageFolder = Folder.selectDialog("Select top folder to process");
var folderList=[];
if (imageFolder != null)  {
processFolder(imageFolder);
folderList.unshift(imageFolder);
createPNGfromJPG(folderList);
function createPNGfromJPG(folderList){
for(var a in folderList){
  var fileList = folderList[a].getFiles ("*.jpg");
   for (var z in fileList){
    var file = fileList[z];
    open(file);
    var Name = fileList[z].name.replace(/\.[^\.]+$/, '');
    var saveFile = File(decodeURI(fileList[z].path+"/"+Name+".png"));
    FitImage(640,640); //Resizes  to the longest size
    //FitImage(128,128);
    savePNG8SFW(saveFile);
    app.activeDocument.close(SaveOptions.DONOTSAVECHANGES);
function processFolder(folder) {
    var fileList = folder.getFiles()
     for (var i = 0; i < fileList.length; i++) {
        var file = fileList[i];
if (file instanceof Folder) {
  folderList.push(file); 
       processFolder(file);
function savePNG8SFW(saveFile) {
    var desc8 = new ActionDescriptor();
        var desc9 = new ActionDescriptor();
        desc9.putEnumerated( charIDToTypeID('Op  '), charIDToTypeID('SWOp'), charIDToTypeID('OpSa') );
        desc9.putEnumerated( charIDToTypeID('Fmt '), charIDToTypeID('IRFm'), charIDToTypeID('PNG8') );
        desc9.putBoolean( charIDToTypeID('Intr'), false );
        desc9.putEnumerated( charIDToTypeID('RedA'), charIDToTypeID('IRRd'), charIDToTypeID('Sltv') );
        desc9.putBoolean( charIDToTypeID('RChT'), false );
        desc9.putBoolean( charIDToTypeID('RChV'), false );
        desc9.putBoolean( charIDToTypeID('AuRd'), false );
        desc9.putInteger( charIDToTypeID('NCol'), 256 ); //Number of colours.
        desc9.putEnumerated( charIDToTypeID('Dthr'), charIDToTypeID('IRDt'), charIDToTypeID('Dfsn') );
        desc9.putInteger( charIDToTypeID('DthA'), 100 );
        desc9.putInteger( charIDToTypeID('DChS'), 0 );
        desc9.putInteger( charIDToTypeID('DCUI'), 0 );
        desc9.putBoolean( charIDToTypeID('DChT'), false );
        desc9.putBoolean( charIDToTypeID('DChV'), false );
        desc9.putInteger( charIDToTypeID('WebS'), 0 );
        desc9.putEnumerated( charIDToTypeID('TDth'), charIDToTypeID('IRDt'), charIDToTypeID('None') );
        desc9.putInteger( charIDToTypeID('TDtA'), 100 );
        desc9.putBoolean( charIDToTypeID('Trns'), true );
        desc9.putBoolean( charIDToTypeID('Mtt '), false );
        desc9.putInteger( charIDToTypeID('MttR'), 255 );
        desc9.putInteger( charIDToTypeID('MttG'), 255 );
        desc9.putInteger( charIDToTypeID('MttB'), 255 );
        desc9.putBoolean( charIDToTypeID('SHTM'), false );
        desc9.putBoolean( charIDToTypeID('SImg'), true );
        desc9.putBoolean( charIDToTypeID('SSSO'), false );
            var list3 = new ActionList();
        desc9.putList( charIDToTypeID('SSLt'), list3 );
        desc9.putBoolean( charIDToTypeID('DIDr'), false );
        desc9.putPath( charIDToTypeID('In  '),File( saveFile) );
    desc8.putObject( charIDToTypeID('Usng'), stringIDToTypeID('SaveForWeb'), desc9 );
    executeAction( charIDToTypeID('Expr'), desc8, DialogModes.NO );
function FitImage( inWidth, inHeight ) {
if ( inWidth == undefined || inHeight == undefined ) {
  alert( "FitImage requires both Width & Height!");
  return;
var desc = new ActionDescriptor();
var unitPixels = charIDToTypeID( '#Pxl' );
desc.putUnitDouble( charIDToTypeID( 'Wdth' ), unitPixels, inWidth );
desc.putUnitDouble( charIDToTypeID( 'Hght' ), unitPixels, inHeight );
var runtimeEventID = stringIDToTypeID( "3caa3434-cb67-11d1-bc43-0060b0a13dc4" );
executeAction( runtimeEventID, desc, DialogModes.NO );