JSFiddle - React, Tailwind, and code Playground

HTML

<div class="test1">
    <img src="http://placekitten.com/g/700/300" /><br>
    <img src="http://placekitten.com/g/500/300" /><br>
    <img src="http://placekitten.com/g/300/300" /><br>
    <img src="http://placekitten.com/g/300/700" /><br>
    <img src="http://placekitten.com/g/500/700" /><br>
    <img src="http://placekitten.com/g/700/700" />
</div>

CSS

.test1, .test2 {
    outline: 5px solid;
    margin: 20px;
}

JavaScript

$(function(){
  $('.test1 img').each(function(){
    $(this).width(($(this).height() > $(this).width())?'60%':'95%');
  });
});