Re: Batch or script..plug-in?

Could you give this a try?

It assumes the files are in order.

// merge images in folder;

// 2014, use it at your own risk;

#target photoshop

// dialog for folder-selection;

var theFolder = Folder.selectDialog ("select folder");

if (theFolder) {

var theFiles = theFolder.getFiles(getSomeFiles);

// create the psd-options;

psdOpts = new PhotoshopSaveOptions();

psdOpts.embedColorProfile = true;

psdOpts.alphaChannels = false;

psdOpts.layers = true;

psdOpts.spotColors = true;

// the number of files to combine;

var theNumber = 3;

// work through files;

for (var m = 0; m < theFiles.length / theNumber; m++) {

          var thisNumber = m * theNumber;

          var theFile = app.open(File(theFiles[thisNumber]));

// place;

          for (var n = 1; n < theNumber; n++) {

                    thisNumber++;

                    if (File(theFiles[thisNumber]).exists == true) {placeFile (theFiles[thisNumber])}

                    };

// save the combined files;

          theFile.saveAs(new File (theFolder +"/"+ theFile.name.replace(/\.\D{3,4}$/i, "_comb.psd")), psdOpts);

          theFile.close(SaveOptions.DONOTSAVECHANGES)

          }

};

////////////////////////////////////

////// get psds, tifs and jpgs from files //////

function getSomeFiles (theFile) {

    if (theFile.name.match(/\.(jpg|tif|psd|pdf|)$/i)) {

        return true

        };

          };

////// place file //////

function placeFile (thePath) {

// =======================================================

var idPlc = charIDToTypeID( "Plc " );

    var desc14 = new ActionDescriptor();

    var idnull = charIDToTypeID( "null" );

    desc14.putPath( idnull, new File( thePath ) );

    var idFTcs = charIDToTypeID( "FTcs" );

    var idQCSt = charIDToTypeID( "QCSt" );

    var idQcsa = charIDToTypeID( "Qcsa" );

    desc14.putEnumerated( idFTcs, idQCSt, idQcsa );

    var idOfst = charIDToTypeID( "Ofst" );

        var desc15 = new ActionDescriptor();

        var idHrzn = charIDToTypeID( "Hrzn" );

        var idPxl = charIDToTypeID( "#Pxl" );

        desc15.putUnitDouble( idHrzn, idPxl, 0.000000 );

        var idVrtc = charIDToTypeID( "Vrtc" );

        var idPxl = charIDToTypeID( "#Pxl" );

        desc15.putUnitDouble( idVrtc, idPxl, 0.000000 );

    var idOfst = charIDToTypeID( "Ofst" );

    desc14.putObject( idOfst, idOfst, desc15 );

    var idWdth = charIDToTypeID( "Wdth" );

    var idPrc = charIDToTypeID( "#Prc" );

    desc14.putUnitDouble( idWdth, idPrc, 100 );

    var idLnkd = charIDToTypeID( "Lnkd" );

    desc14.putBoolean( idLnkd, true );

executeAction( idPlc, desc14, DialogModes.NO );

};