var message = "Hi, I am now going to create an image for you and save it on your desktop. Would you like to continue?";

var answer = confirm (message);
if(answer)  {
    createImage();
 }

function createImage() {
    // Set units to pixels
    app.preferences.rulerUnits = Units.PIXELS;
    app.preferences.typeUnits  = TypeUnits.PIXELS;
    
    // Define document properties
    var width  = 1024;
    var height = 768;
    var res    = 72;
    var name   = "AsyncJS";
    var mode   = NewDocumentMode.RGB;
    var fill   = DocumentFill.TRANSPARENT;
    var ratio  = 1;
    
    // Create new document
    var doc = app.documents.add(width, height, res, name, mode, fill, ratio);
    
    // Set up the background layer
    var backgroundLayer  = doc.artLayers[0];
    backgroundLayer.name = "Background";
    
    // Create random colors
    app.foregroundColor.rgb.red   = Math.random() * 255;
    app.foregroundColor.rgb.green = Math.random() * 255;
    app.foregroundColor.rgb.blue  = Math.random() * 255;
    app.backgroundColor.rgb.red   = 0;
    app.backgroundColor.rgb.green = 0;
    app.backgroundColor.rgb.blue  = 0;
    // Apply clouds to the background layer based on these random colors
    backgroundLayer.applyClouds();
    
    // applyLensFlare(brightness, flareCenter[], LensType   
    
    // Add a text layer
    var textLayer  = doc.artLayers.add();
    textLayer.name = "Text";
    textLayer.kind = LayerKind.TEXT;
    // Create the text item
    var textItem   = textLayer.textItem;
    textItem.contents = "Async.js";
    textItem.font     = "Helvetica";
    textItem.size     = 128;
    textItem.fauxBold = true;
    textItem.position = [width/2, height/2];
    textItem.justification = Justification.CENTER;
    // Set the color to white
    textItem.color.rgb.red   = 255;
    textItem.color.rgb.green = 255;
    textItem.color.rgb.blue  = 255;
    // Apply a blend mode
    textLayer.blendMode = BlendMode.SOFTLIGHT;
    
    // Name of the file we are going to ExportOptions
    var filename = "~/Desktop/async-" + new Date().getTime() + ".png";
    var file     = File(filename);
    
    // Type of export we are doing
    var exportType = ExportType.SAVEFORWEB;

    // Save for web options
    var options     = new ExportOptionsSaveForWeb();
    options.format  = SaveDocumentType.PNG;
    options.quality = 100;
    
    // Export to disk
    doc.exportDocument (file, ExportType.SAVEFORWEB, options);
    
    // Close the document without saving
    doc.close(SaveOptions.DONOTSAVECHANGES);    
}