.hover-image-swap{position:relative}.hover-image-swap img{display:block;transition:opacity 0.4s ease-in-out}.hover-image-swap::after{content:"";background-image:url('https://yourwebsite.com/path-to-hover-image.jpg');background-size:cover;background-position:center;position:absolute;top:0;left:0;right:0;bottom:0;opacity:0;transition:opacity 0.4s ease-in-out}.hover-image-swap:hover::after{opacity:1}