.lazy-hidden,
.entry img.lazy-hidden,
img.thumbnail.lazy-hidden {
  background-color: #ffffff;
  background-image: url("loading.gif");
  background-repeat: no-repeat;
  background-position: 50% 50%;
}
figure.wp-block-image img.lazy-hidden {
  min-width: 150px;
}
picture source[type="image/webp"] {
  display: block;
}