JSFiddle - React, Tailwind, and code Playground

HTML

<div id="first">
    Hover
    <div id="on-hover">
        <img src="https://www.juegaenlinea.com/images/juega-en-vivo-blackjack33.png" />
    </div>
</div>

CSS

#first:hover > #on-hover{
    opacity:1;
}

#on-hover{
    opacity:0;
    -webkit-transition: opacity 0.5s;
}

#first{
    width:300px;
    height:200px;
}