JSFiddle - React, Tailwind, and code Playground

HTML

<img src="https://imagizer.imageshack.us/v2/350x496q90/822/z7ds.jpg" />

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");
    -webkit-filter: grayscale(100%);
    -moz-filter:    grayscale(100%);
    -ms-filter:     grayscale(100%);
    -o-filter:      grayscale(100%);
    filter: gray; 
}

img:hover {
    filter: none;
    -webkit-filter: grayscale(0%);
    -moz-filter:    grayscale(0%);
    -ms-filter:     grayscale(0%);
    -o-filter:      grayscale(0%);
    cursor: pointer;
}