The HTML
<a class="video-thumb-wrapper"
href="//www.youtube.com/embed/myk22AuwizE">
<img class="video-thumb" width="280" height="200"
src="//img.youtube.com/vi/myk22AuwizE/0.jpg" />
</a>
The CSS
.video-thumb-wrapper { display: block; width: 280px; height: 200px;
background: url('/img/play.png') center center no-repeat; }
.video-thumb { filter: alpha(opacity = 40); opacity: .4; }
/* set width and height of the wrapper to the width and height of the thumbnail itself */
Add a lightbox to the video-thumb-wrapper class to make it even more functional.