JSFiddle - React, Tailwind, and code Playground

HTML

<div id="masthead">
    <img src="http://i.imgur.com/K9aZKGI.png" />
</div>

CSS

#masthead { width:100% ;
    height:auto ;
    max-height:350px ;
    background:navy ;
    text-align:center ;
    overflow:hidden ;
}

#masthead img { width:100% ;
    max-width:300px ;
    height:auto ;
    margin:0 auto ;
}