Hello,

this is custom work but if you wan to to implement it yourself:

open /sections/blog_post_section.php

you will see

<div class="article-img" style="background-image: url(<?php echo esc_url( $grenada_post_image[0] ); ?>)"></div>

that's the hovered image you want to transform into a post image

if you open /js/scripts.js you will find the following code that handles the blog post image:

$("#ball").append('<div class="image-tooltip"></div>');
$("#blog").find("article .article-img").each(function() {
$(".image-tooltip").append($(this))
}), $("#blog").find("article a.post-title").on("mouseenter", function(e) {
$(".image-tooltip").children().eq($(this).parent().parent().parent().index()).addClass("hover")
}).on("mouseleave", function(e) {
$(".image-tooltip").children().eq($(this).parent().parent().parent().index()).removeClass("hover")
}).on("click", function() {
$(".image-tooltip").children().eq($(this).parent().parent().parent().index()).removeClass("hover")
TweenMax.to('#ball', 0.2,{borderWidth: "2px",scale: 1});
});