React get NodeList of children (components)

I have created a react application, which contains posts (with image or text). I have to make sure, that the images are loaded as soon the get displayed, to avoid 'jumping' of the images. I have found a javascript package imagesloaded desandro which detects when images have been loaded.

    // Container.js
    render() {
    let item;
    // Array of all items
    let items = this.props.items;

    if (this.props.items) {
      // Map through the items
      item = items.map(item => {
        // Item with only text
        if (item.imageUrl === undefined && item.text) {
          return (
            // Item without image (only Text)
            <TextItem
              item={item}
              styles={this.props.styles}
            />
          );

          // Item without text (only image)
        } else if (item.imageUrl && item.text === undefined) {
          return (
            <ImageItem
              post={post}
              styles={this.props.styles}
            />
          );
        } 
      });
    }
    return <div className="item-container">{item}</div>;
  }

But when I call the function to check if the images were loaded, the images were not found, because the aren't rendered yet and I get the error "Bad element for imagesLoaded null". Is it possible to get the node of the items before they get rendered?

// Call function to check if the images were loaded
  componentDidMount(){
    const container = document.querySelector('.container');
    const imgLoad = imagesLoaded(container);
    imgLoad.on( 'progress', function( instance, image ) {
      let result = image.isLoaded ? 'loaded' : 'broken';
      console.log( 'image is ' + result + ' for ' + image.img.src );
    });
  }