appendImage() {
    if (!this.isAttached) {
      return;
    }

    if (this.instance.dispatch('contentAppendImage', {
      content: this
    }).defaultPrevented) {
      return;
    } // ensure that element exists and is not already appended


    if (this.slide && this.element && !this.element.parentNode) {
      this.slide.container.appendChild(this.element);
    }

    if (this.state === LOAD_STATE.LOADED || this.state === LOAD_STATE.ERROR) {
      this.removePlaceholder();
    }
  }
Append the image content to slide container