JSFiddle - React, Tailwind, and code Playground

HTML

<div id="imgGrey"><img width="400" src="http://namasteui.com/wp-content/uploads/2016/01/image-greyscale.jpg"></div>

CSS

#imgGrey img {
filter: gray; /* For IE6-9 */
filter: grayscale(1); /* For Microsoft Edge and Firefox 35+ */
-webkit-filter: grayscale(1); /* For Google Chrome, Safari 6+ & Opera 15+ */
}

/* Now disable grayscale on hover */
#imgGrey img:hover {
filter: none;
-webkit-filter: grayscale(0);
}