How to import image (.svg, .png ) in a React Component

If the images are inside the src/assets folder you can use require with the correct path in the require statement,

var Diamond = require('../../assets/linux_logo.jpg');

 export class ItemCols extends Component {
    render(){
        return (
            <div>
                <section className="one-fourth" id="html">
                    <img src={Diamond} />
                </section>
            </div>
        )
    } 
}

try using

import mainLogo from'./logoWhite.png';

//then in the render function of Jsx insert the mainLogo variable

class NavBar extends Component {
  render() {
    return (
      <nav className="nav" style={nbStyle}>
        <div className="container">
          //right below here
          <img  src={mainLogo} style={nbStyle.logo} alt="fireSpot"/>
        </div>
      </nav>
    );
  }
}

You can use require as well to render images like

//then in the render function of Jsx insert the mainLogo variable

class NavBar extends Component {
  render() {
    return (
      <nav className="nav" style={nbStyle}>
        <div className="container">
          //right below here
          <img src={require('./logoWhite.png')} style={nbStyle.logo} alt="fireSpot"/>
        </div>
      </nav>
    );
  }
}