CSS overlay http://jsfiddle.net/Zf5am/353/ http://stackoverflow.com/questions/5647619/overlay-transparent-image-on-hover-using-css

Overlay

<div class="image">
    <img src="xy.jpg" alt="" />
    <img class="hoverimage" src="xy_hover.jpg" alt="" />
</div>
CSS:

.image { position: relative; width: 184px; height: 219px; }
.hoverimage { position: absolute; top: 0; left: 0; display: none; }
.image:hover .hoverimage { display: block; }