can't make my JS script to work in Photoshop

@silk1975 

The following code will give you a result, however, I had to comment out some code that you will need to work on further...

// Capture and set the original ruler units to pixels
var origUnits = app.preferences.rulerUnits;
app.preferences.rulerUnits = Units.PIXELS;

// Background image directory and name
var backgroundDir = new Folder("~/Desktop/bg_image");
var backgroundFile = new File(backgroundDir + "/" + "background_image.jpg");

// Logos directory and files
var logoDir = new Folder(backgroundDir + "/" + "logo");
var logoFiles = logoDir.getFiles("*.png");

// logo loop
for (var i = 0; i < logoFiles.length; i++) {

    // open background image and get current logo
    var backgroundDoc = app.open(backgroundFile);
    var logoFile = logoFiles[i];

    // New Layer for logo and load it
    var logoLayer = backgroundDoc.artLayers.add();

    placeFile(new File(logoFile), false, 0, 0);


    // Resize logo and Set logo height to 90% of background height
    //var logoHeight = backgroundDoc.height * 0.9;
    //logoLayer.resize(undefined,logoHeight);

    // Center logo on the picture
    //logoLayer.translate(backgroundDoc.width / 2 - logoLayer.bounds.width / 2, backgroundDoc.height / 2 - logoLayer.bounds.height / 2);

    // final save 
    var finalDir = new Folder(backgroundDir + "/" + "final");
    if (!finalDir.exists) {
        finalDir.create();
    }
    var finalFile = new File(finalDir + "/" + logoFile.name.replace(/\.[^\.]+$/, '') + "_final.jpg");
    backgroundDoc.saveAs(finalFile, new JPEGSaveOptions(), true);

    // close background image
    backgroundDoc.close(SaveOptions.DONOTSAVECHANGES);
}

// Restore the original ruler units
app.preferences.rulerUnits = origUnits;

function placeFile(null2, linked, horizontal, vertical) {
    var s2t = function (s) {
        return app.stringIDToTypeID(s);
    };
    var AD = new ActionDescriptor();
    AD.putInteger(s2t("ID"), 1);
    AD.putPath(s2t("null"), null2);
    AD.putBoolean(s2t("linked"), linked); // false for embedded
    AD.putEnumerated(s2t("freeTransformCenterState"), s2t("quadCenterState"), s2t("QCSAverage"));
    AD.putUnitDouble(s2t("horizontal"), s2t("pixelsUnit"), horizontal);
    AD.putUnitDouble(s2t("vertical"), s2t("pixelsUnit"), vertical);
    AD.putObject(s2t("offset"), s2t("offset"), AD);
    executeAction(s2t("placeEvent"), AD, DialogModes.NO);
}

Please compare your original code to this edited version.

Note that the following has been disabled, you will need to put in more work to correct it:

    // Resize logo and Set logo height to 90% of background height
    //var logoHeight = backgroundDoc.height * 0.9;
    //logoLayer.resize(undefined,logoHeight);

    // Center logo on the picture
    //logoLayer.translate(backgroundDoc.width / 2 - logoLayer.bounds.width / 2, backgroundDoc.height / 2 - logoLayer.bounds.height / 2);

@silk1975 

In addition to the previously mentioned issues with your various paths, there is an issue with this line:

logoLayer.place(logoFile);

Where did you get that code? From ChatGPT?

There is no .place method for artLayer or artLayers. 

So instead of using standard DOM code (Document Object Model), you will need AM code (Action Manager). The most commonly available method is to use the ScriptingListener plug-in to record (and then edit as required) the image placement process.

You open a folder called "bg_image" and one called "logo". But how does Photoshop know where to look for these? 

I suggest as well as using full paths, you add some messages to track your progress through the script.