The thumbnails on your page are upscaled. you are using 300×300 thumbnails but show them in 387×387… wither make the thumbnail size smaller or use a bigger size for thumbnail images and regenerate. Hope this helps
I second this opinion. I am running the plugin in two woocommerce shops and on both it sends emails to customers who already finalized a sale. This makes customers insecure, weather or not their order went through.