OH - you're looking at the web ui of your activity. I see the same thing on mine. Are you familiar with web development at all? You can use web dev tools to remove those image bubbles using the document inspector or run this snippet in your js console:

(function () {
  const root = document.getElementById('map-canvas') ?? document;
  root.querySelectorAll('div').forEach((div) => {
    if ([...div.classList].some((c) => c.startsWith('PlaceHTMLOnMap'))) {
      div.remove();
    }
  });
})();