Autosizing images based on aspect ratio

HTML

<div class="container">
    <img src="http://placekitten.com/240/300">
</div>

<h3 style="clear: both;">Full Size Image - For Reference</h3>
<img src="http://placekitten.com/240/300">

CSS

.container {
    background-color:#000;
    width:100px;
    height:200px;
    
    display:flex;
    justify-content:center;
    align-items:center;
    overflow:hidden;
    
}

JavaScript

$(".container").each(function(){
    var divH = $(this).height()
    var divW = $(this).width()
    var imgH = $(this).children("img").height();
    var imgW = $(this).children("img").width();
    
    if ( (imgW/imgH) < (divW/divH)) { 
        $(this).addClass("1");
        var newW = $(this).width();
        var newH = (newW/imgW) * imgH;
        $(this).children("img").width(newW); 
        $(this).children("img").height(newH); 
    } else {
        $(this).addClass("2");
        var newH = $(this).height();
        var newW = (newH/imgH) * imgW;
        $(this).children("img").width(newW); 
        $(this).children("img").height(newH); 
    }
})