JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://lorempixel.com/200/200" />

CSS

img {
    -webkit-transition: all .5s ease;
    -moz-transition: all .5s ease;
    -ms-transition: all .5s ease;
    -o-transition: all .5s ease;
    transition: all .5s ease;
    -webkit-filter: grayscale(100%);
    -moz-filter: grayscale(100%);
    -ms-filter: grayscale(100%);
    -o-filter: grayscale(100%);
    filter: grayscale(100%);
    filter: url(grayscale.svg); /* Firefox 4+ */
    filter: gray; /* IE 6-9 */
}
img:hover {
  -webkit-filter: grayscale(0%);
  -moz-filter: grayscale(0%);
  -ms-filter: grayscale(0%);
  -o-filter: grayscale(0%);
  filter: grayscale(0%);
  filter: none;
}