Code.js

function onInstall(e) {
  onOpen(e);
}

function onOpen(e) {
  SlidesApp.getUi()
    .createMenu("Insert Images")
    .addItem("Insert Images", "init")
    .addToUi();
}

function include(filename) {
  return HtmlService.createHtmlOutputFromFile(filename).getContent();
}

function getHTML() {
  return HtmlService.createTemplateFromFile("index.html")
    .evaluate()
    .setTitle("CC Search");
}

function init() {
  var htmlOut = getHTML();

  // Display the sidebar
  SlidesApp.getUi().showSidebar(htmlOut);
}

function insertImage(url, attribution, numImages, attribLoc) {
  var currentSlide = SlidesApp.getActivePresentation()
    .getSelection()
    .getCurrentPage()
    .asSlide();
  var numOfSlideGroups = currentSlide.getGroups().length + 1;
  if (numOfSlideGroups < numImages) {
    numImages = numOfSlideGroups;
  }
  var offset = numImages * 10 + 10;
  var fontSize = 8;
  var currentImage = currentSlide.insertImage(url);
  var currentImageText;
  if (attribLoc.image) {
    currentImageText = currentSlide.insertTextBox(attribution);
  } else {
    currentImageText = currentSlide.insertTextBox(numImages + "*");
  }
  currentImageText
    .getText()
    .getTextStyle()
    .setFontSize(fontSize)
    .setBackgroundColor(0, 0, 0)
    .setForegroundColor(255, 152, 0);
  var groupList = [currentImage, currentImageText];
  currentSlide.group(groupList);
  var slideWidth = SlidesApp.getActivePresentation().getPageWidth();
  var slideHeight = SlidesApp.getActivePresentation().getPageHeight();

  if (attribLoc.footer) {
    currentSlide
      .insertTextBox(
        "[" + numImages + "] " + attribution,
        0,
        slideHeight - offset,
        720,
        20
      )
      .bringToFront()
      .getText()
      .getTextStyle()
      .setFontSize(fontSize)
      .setBackgroundColor(255, 152, 0);
  }
}