Fix gap on a Wordpress theme, which uses jetpack masonry and imagesloaded lazyload.

javascript.js

/**
 * Add or try this in file masonryInitializer.js
 * Source: https://github.com/desandro/imagesloaded/issues/303
 *
 */

(function ($) {

    "use strict";

    $(document).ready(function () {
        // init Masonry
        var $grid = $('.msnry-grid').masonry({
            itemSelector: '.msnry-grid-item',
            columnWidth: '.msnry-grid-sizer',
            percentPosition: true,
        });

        // layout Masonry after each image loads
        $grid.find('[loading="lazy"]').on('load', function() {
            $('.msnry-grid').masonry('layout');
        })
    });

})(jQuery);