imgDimensions.js

class ImgDimensions extends React.Component {
  state = {width: 0, height: 0, errored: false};

  constructor() {
    this.onLoad = this.onLoad.bind(this);
    this.onError = this.onError.bind(this);
  }

  onLoad({target: {height, width}}) {
    this.setState({width, height});
  }
  
  onError() {
    this.setState({errored: true}); 
  }

  render() {
    const {width, height} = this.state;

    return (
      <div>
        <div>{width}x{height}</div>
        <img onLoad={this.onLoad} onError={this.onError} />
      </div>
    );
  }
}