Images.js

var wptImages = function (win) {
  var images = [];
  if (win) {
    var doc = win.document;
    var elements = doc.getElementsByTagName("*");
    for (var i = 0; i < elements.length; i++) {
      var el = elements[i];
      if (el.tagName == "IMG") {
        var url = el.currentSrc || el.src;

        // Only include HTTP(S) URLs i.e. skip dataURIs
        if (url.indexOf("http") === 0) {
          images.push({
            url: url,
            width: el.width,
            height: el.height,
            naturalWidth: el.naturalWidth,
            naturalHeight: el.naturalHeight,
            loading: el.getAttribute("loading"),
            decoding: el.getAttribute("decoding"),
            fetchpriority: el.getAttribute("fetchpriority"),
            inViewport:
              el.getBoundingClientRect().bottom >= 0 &&
              el.getBoundingClientRect().right >= 0 &&
              el.getBoundingClientRect().top <= window.innerHeight &&
              el.getBoundingClientRect().left <= window.innerWidth,
          });
        }
      }
      if (el.tagName == "IFRAME") {
        try {
          var im = wptImages(el.contentWindow);
          if (im && im.length) {
            images = images.concat(im);
          }
        } catch (e) {
          // continue regardless of error
        }
      }
      if (images.length > 10000) break;
    }
  }
  return images;
};

return JSON.stringify(wptImages(window));