JSFiddle - React, Tailwind, and code Playground

HTML

<div class="flex_wrap">
  <div class="flex_item">
    <img src="https://photolium.net/uploads/posts/2017-03/1489180781_4-hosico-real-life-puss-in-boots.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://murkote.com/wp-content/uploads/2016/12/kamyshoviy-kot-4.jpg.pagespeed.ce.FbBWOkp8Tg.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://static1.repo.aif.ru/1/34/714704/f12a352fac8d4141f832434b7a8133e0.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="https://www.segodnya.ua/img/gallery/10693/52/796829_main.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://static1.repo.aif.ru/1/34/714704/f12a352fac8d4141f832434b7a8133e0.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://murkote.com/wp-content/uploads/2016/12/kamyshoviy-kot-4.jpg.pagespeed.ce.FbBWOkp8Tg.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="https://content.onliner.by/news/1100x5616/c7e920c94171ff2144c06e451a8cc982.jpeg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://static1.repo.aif.ru/1/34/714704/f12a352fac8d4141f832434b7a8133e0.jpg" alt="">
  </div>
  <div class="flex_item">
    <img src="http://kot-pes.com/wp-content/uploads/2015/06/Abissinskii_kot_05-650x977.jpg" alt="">
  </div>
  <div class="flex_item">
    <img...

CSS

.flex_wrap {
  width: 100%;
  padding: 15px;
  display: flex;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  flex-wrap: wrap;
  flex-direction: column;
}

.flex_item {
  height: auto;
  paddin-bottom: 3px;
  width: 20%;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  margin-left: 3px;
  margin-right: 3px;
}

.flex_item:empty {
  width: 0;
}

.flex_item img {
  width: 100%;
  height: auto;
}

JavaScript

function wrapperHeight() {
	var itemsHeight = 0;
	$('.flex_item').each(function() {
  	itemsHeight = itemsHeight + $(this).height();
  });
	$('.flex_wrap').css('height', itemsHeight/5);
}

wrapperHeight();

$( window ).resize(function() {
	wrapperHeight();
});