code: protected @Nullable HtmlElement<?> getPictureElement(@NotNull Media media) {
      PictureSource[] pictureSources = media.getMediaRequest().getMediaArgs().getPictureSources();
  
      Picture picture = new Picture();
  
      // add source elements (only if matching renditions found)
      boolean foundAnySource = false;
      for (PictureSource pictureSource : pictureSources) {
        Source source = new Source();
        if (pictureSource.getMedia() != null) {
          source.setMedia(pictureSource.getMedia());
        }
        String srcSet = getSrcSetRenditions(media, pictureSource.getMediaFormat(), pictureSource.getWidths());
        if (srcSet != null) {
          source.setSrcSet(srcSet);
          picture.add(source);
          foundAnySource = true;
        }
      }
  
      // add image element
      HtmlElement<?> image = getImageElement(media);
      if (image == null) {
        return null;
      }
  
      if (foundAnySource) {
        picture.add(image);
        return picture;
      }
      else {
        return image;
      }
    }
docs: Create an <code>img</code> element that displays the given rendition image.
  @param media Media metadata
  @return <code>img</code> element with properties or null if media metadata is invalid