JSFiddle - React, Tailwind, and code Playground

HTML

<div class="post-entry">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
</div>
<div class="post-entry">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
    <img src="" alt="">
</div>

JavaScript

var image_data = [];
$('.post-entry').each(function(i) {

    image_data[i] = $(this).find('img').map(function() {
      var self = $(this);
      return {
        big: self.hasClass('big') || self.hasClass('medium'),
        offset: self.offset(),
        width: self.width(),
        height: self.height()
      };
    }).get();
    
  });

console.log(image_data);