wordpress welcome page

It’s not a plugin – only Javascript dhtml. View source reveals:
<div id="featured"><img id="screenie" src="https://two.wordpress.com/style/screenshots/ss-1.png" /></div>

<div id="others">
<span><img onmouseover="document.getElementById('screenie').src='https://two.wordpress.com/style/screenshots/ss-1.png'&quot; src="https://two.wordpress.com/style/screenshots/ss-1-thumb.png&quot; /></span>
<span><img onmouseover="document.getElementById('screenie').src='https://two.wordpress.com/style/screenshots/ss-2.png'&quot; src="https://two.wordpress.com/style/screenshots/ss-2-thumb.png&quot; /></span>
<span><img onmouseover="document.getElementById('screenie').src='https://two.wordpress.com/style/screenshots/ss-3.png'&quot; src="https://two.wordpress.com/style/screenshots/ss-3-thumb.png&quot; /></span>
</div>

The <div id="others"> has <span>‘s, that when rollover’ed changes the image src of the <img id="screenie"> using the DOM access method getElementById.

Good luck!