Open met de inspector tools van je browser de console tab en plak de onderstaande code.

function findATFLazyLoadedImages() {
  const lazy = document.querySelectorAll('[loading="lazy"]');
  let flag = false;
  lazy.forEach((tag) => {
    const position = parseInt(tag.getBoundingClientRect().top);
    if (position < window.innerHeight && position !== 0) {
      console.log(tag, position);
      flag = true;
    }
  });

  return flag;
}

console.log(findATFLazyLoadedImages());