This is one of the best CSS techniques for the perfect full background image. There are a few different ways we can go about it. I prefer using a bit more dynamic approach.

Static CSS Class/ID:
This is ideal if you are going to use a full background image only once.

More Dynamic Approach:
When I used this method, I can call “full-bg-size” class as many times as I want. The only requirement would be, using the background-image property inline style.

.full-bg-size { 
  background: url(images/bg.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}
<div class="full-bg-size-component" style="background-image: url('image-url.jpg');">
//Content
</div>
.full-bg-size-component { 
  background-repeat: no-repeat; 
  background-position: center center;
  background-attachment: fixed;
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

React 16 – Component Version:

Here is the React version of full background covered image. You should check it out on full page view. I use this technique for a few of the projects I have worked for.

See the Pen React 16 - Full Bg Cover Component by Timurtek Bizel (@Timurtek) on CodePen.

Browser Compatibility: Chrome,Safari 3+, Firefox 3.6+, IE 9+, Opera 10+