Not doing anything

I installed the plugin, regenerated thumbnails as required and for some reason, the new images are not being used.

<img width="700" height="700" src="https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg" class="attachment-shop_single size-shop_single wp-post-image" alt="" title="" data-caption="" data-src="https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg" data-large_image="https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg" data-large_image_width="1200" data-large_image_height="1200" srcset="https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg 300w, https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg 100w, https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg 700w, https://kumplo.com/wp-content/uploads/2020/05/pizza-socks-kumplo.jpg 1200w" sizes="(max-width: 700px) 100vw, 700px">

The page I need help with: [log in to see the link]