JSFiddle - React, Tailwind, and code Playground
HTML
<div><img id="black" src="http://www.ratemotorcycle.com/image1/5/53/kawasaki-ninja-zx10r-2013.jpg"/><img id="red" src="http://imageshack.us/a/img39/3517/13kawasakizx10r1.jpg"/></div>
CSS
#black{
position:absolute;
z-index:2;
color:black;
font-weight:bold;
font-size:2em;
width:768px;
}
#red {
position:absolute;
z-index:10;
left:8px;
width:0px;
overflow:hidden;
font-weight:bold;
font-size:2em;
color:red;
}
JavaScript
var red = document.getElementById('red');
red.style.width = "0px";
red.style.height = "1024px";
var animation = setInterval(function(){
if(parseInt(red.style.width,10) == 768)
clearInterval(animation);
red.style.width = parseInt(red.style.width,10)+2 +"px";
},10);