title: How to set Angular 4 background image?
body: <p>I am trying the following lines to set the background image.but it not works. what are the way set background image in constantly in my application.</p>
  
  <p><strong>app.component.html</strong></p>
  
  <pre><code>&lt;div [ngStyle]="{'background' : 'url(./images/trls.jpg)'}"&gt;
      &lt;router-outlet&gt;&lt;/router-outlet&gt;
      &lt;alert&gt;&lt;/alert&gt;
  &lt;/div&gt;
  </code></pre>