Why is the Excel File exported from a Suitelet corrupted when adding an image?

Hi There

I have the following code which exports the search results into a table in Excel.

That part works fine.

However, I am trying to add an image from the filing cabinet which is resulting in the file becoming corrupted.

Why is that? Is it not possible to add an image file ?

/**
 *@NApiVersion 2.x
 *@NScriptType Suitelet
 */
define(["N/file", "N/encode", "N/search"], function (file, encode, search) {
  function onRequest(context) {
    if (context.request.method == "GET") {
        // Load the logo image file
      var logoFile = file.load({
        id: 8143 // Replace with the internal ID of the logo file
      });

      // Get the Base64-encoded image data
      var logoData = logoFile.getContents({
        encoding: