JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://i1.ytimg.com/vi/XWGszmviDpA/maxresdefault.jpg" class="bg">

CSS

img.bg {
    height: 100%;
    position: fixed;
    left:50%;
}

JavaScript

var i = $('img');
var w = i.width();

i.css({marginLeft: -w/2});

$( window ).resize(function() {
    i.css({marginLeft: -w/2});
});