Photoshop script to save a file in multiple different sizes as a png file

save_multiple_icons.jsx

// Create Multiple icon files
// Author: Patrick Bailey
// License: MIT
//
//Copyright 2017 T. Patrick Bailey
//Permission is hereby granted, free of charge, to any person obtaining a copy 
//of this software and associated documentation files (the "Software"), to 
//deal in the Software without restriction, including without limitation the 
//rights to use, copy, modify, merge, publish, distribute, sublicense, and/or 
//sell copies of the Software, and to permit persons to whom the Software is 
//furnished to do so, subject to the following conditions:
//
//The above copyright notice and this permission notice shall be included in 
//all copies or substantial portions of the Software.
//
//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A 
//PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 
//HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 
//OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE 
//OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//

// bring Photoshop into focus
#target photoshop


main();

function main() {
    app.preferences.rulerUnits = Units.PIXELS;     // use pixels
    var dir = app.activeDocument.path

    //Make a copy
    var docCopy = app.activeDocument.duplicate();
    var origWidth = docCopy.width.value;
    var origHeight = docCopy.height.value;
    var initialPrefs = app.preferences.rulerUnits; // will restore at end

    var sfw = new ExportOptionsSaveForWeb();
    sfw.format = SaveDocumentType.PNG;
    sfw.PNG8 = false; // use PNG-24
    sfw.transparency = true;


    if(origWidth == origHeight){
        // Folder selection dialog
        var destFolder = Folder(dir).selectDlg("Select a Folder to save Icons in");
        // var destFolder = Folder(dir).selectDialog( "Choose an output folder");
        var iconName =prompt("Enter name of icon (all icons will start with this name","","Icon Name");

        var sizeArr = [512, 256, 128, 96, 64, 48, 32, 24, 20, 16 ]
        var goForIt = confirm("This will make the following icon folder sizes [" +sizeArr + "] and the icon prefix name is: " + iconName );
        try {
            if (goForIt) {

                for(i = 0; i < sizeArr.length; i++) {

                    docCopy.resizeImage(UnitValue(sizeArr[i], "px"), UnitValue(sizeArr[i], "px"), null, ResampleMethod.BICUBIC)
                    docCopy.exportDocument(new File(destFolder + "/" + iconName + "_" + sizeArr[i] + ".png"), ExportType.SAVEFORWEB, sfw);

                    //Bring back this for demo purposes
                    // confirm("Size is :" + sizeArr[i]  + " name would be: " + iconName + "_" + sizeArr[i] + ".png")
                }
            }
        }
        catch(exception) {
            confirm("ERROR: " + exception)
        }
        finally{
            app.preferences.rulerUnits = initialPrefs; // restore prefs
            if(docCopy != null){
                docCopy.close(SaveOptions.DONOTSAVECHANGES);
            }
        }
    }
    else{
        confirm("Height and width must be identical");
    }
}