JSFiddle - React, Tailwind, and code Playground

HTML

<form method="post">
    <span class="icon">
        <input name="submit" type="submit" value=" "/>
    </span>
</form>

CSS

input[type=submit]{
    background:transparent;
    width:20px;
    height:20px;
    border:none;
    padding:none;
    cursor:pointer;
}
.icon{
    float:left;
    background-color:transparent;
    background-image:url(http://www.lcda.fr/pneu-expo/images/drapeau_rond_gb-on.png);
    height:20px;
    width: 20px;
    background-position:center;
    border:none;
    cursor:pointer;
    background-size: 100%;    
}