@btopro shared a cool way of using the Image() API to lazyload images

index.js

    if (attr === "srcconverted" && this.src != "" && !this.rendering) {
      this.rendering = true;
      // loads the image in the background in-case of quality change
      // also then supports failure events
      let i = new Image();
      i.onload = () => {
        this.render(this.srcconverted);
      };
      // try loading just the normal one if this bombed
      i.onerror = () => {
        this.render(this.src);
      };
      i.src = this.srcconverted;
    }