JSFiddle - React, Tailwind, and code Playground

HTML

<div class="post_body">
   <!--IMG z ahref-->
<a href="http://i.imgur.com/lmaJG.jpg" class="lightview limg"><img src="http://i.imgur.com/lmaJGl.jpg" alt=""/></a>
    <!--IMG bez ahref-->
<img src="http://placekitten.com/200/300" alt="bez href"/>
    
</div>

CSS

.post_body img {max-width:200px;max-height:200px;}
.post_body .limg {background-color:blue;}

JavaScript

$('div.post_body').each(function() {
    $(this).find('img').each(function () {
        var img = $(this);
        if (img.is('a') !== true) {
            img.wrap( 
                 $('<a/>').attr('href', img.attr('src')).addClass('lightview limg');
            );
        }
    ));
});