JSFiddle - React, Tailwind, and code Playground

HTML

<img class="grayscale" src="http://4.bp.blogspot.com/-IzPWLqY4gJ0/T01CPzNb1KI/AAAAAAAACgA/_8uyj68QhFE/s1600/a2cf7051-5952-4b39-aca3-4481976cb242.jpg" width="400"><br>
<img class="color" src="http://4.bp.blogspot.com/-IzPWLqY4gJ0/T01CPzNb1KI/AAAAAAAACgA/_8uyj68QhFE/s1600/a2cf7051-5952-4b39-aca3-4481976cb242.jpg" width="400">

CSS

img {
    filter: url("data:image/svg+xml;utf8,<svg xmlns=\'http://www.w3.org/2000/svg\'><filter id=\'grayscale\'><feColorMatrix type=\'matrix\' values=\'0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0.3333 0.3333 0.3333 0 0 0 0 0 1 0\'/></filter></svg>#grayscale"); /* Firefox 3.5+, IE10 */
    filter: gray; /* IE6-9 */
    -webkit-filter: grayscale(100%); /* Google Chrome & Webkit Nightlies */
    -webkit-transition: all .6s ease; /* Fade to color for Google Chrome & Webkit Nightlies */
    -webkit-backface-visibility: hidden; /* Fix for transition flickering */
}

img.grayscale:hover {
    filter: none;
    -webkit-filter: grayscale(0%);
}


img.color {
    filter: none;
    -webkit-filter: grayscale(0%);
}