JSFiddle - React, Tailwind, and code Playground

HTML

<img src="http://www.horseracinglays.com/uploads/image_football006.jpg"  />

CSS

img {
    opacity: 0.6;
    transition: opacity 1s ease-in-out;
    -moz-transition: opacity 1s ease-in-out;
    -webkit-transition: opacity 1s ease-in-out;
}
img:hover {
    opacity: 1.0;
    transition: opacity .55s ease-in-out;
    -moz-transition: opacity .55s ease-in-out;
    -webkit-transition: opacity .55s ease-in-out;
}