.dave-swap-image{
 position:relative;
 display:inline-block;
}

.dave-swap-image img{
 height:100%;
 width:auto;
 max-width:100%;
 display:block;
 transition:opacity var(--duration,300ms);
}

.dave-swap-image .img-2{
 position:absolute;
 inset:0;
 opacity:0;
}

.dave-swap-image:hover .img-2{opacity:1}
.dave-swap-image:hover .img-1{opacity:0}