jquery円形回転画像スクロール切り替え効果

<div id="rotatescroll"> 
<div class="viewport"> 
<ul class="overview"> 
<li><img src="images/SF1.jpg" alt="Chun-Li" /></li> 
<li><img src="images/SF2.jpg" alt="VEGA" /></li> 
<li><img src="images/SF3.jpg" alt="DHAISIM" /></li> 
<li><img src="images/SF4.jpg" alt="KEN" /></li> 
<li><img src="images/SF5.jpg" alt="BALROG" /></li> 
<li><img src="images/SF6.jpg" alt="CAMMY" /></li> 
<li><img src="images/SF7.jpg" alt="GOUKI" /></li> 
<li><img src="images/SF8.jpg" alt="BLANKA" /></li> 
<li><img src="images/SF9.jpg" alt="HONDA" /></li> 
<li><img src="images/SF10.jpg" alt="FEI LONG" /></li> 
<li><img src="images/SF11.jpg" alt="GUILE" /></li> 
<li><img src="images/SF12.jpg" alt="RYU" /></li> 
<li><img src="images/SF13.jpg" alt="SAGAT" /></li> 
<li><img src="images/SF14.jpg" alt="THWAK" /></li> 
<li><img src="images/SF15.jpg" alt="ZANGIEF" /></li> 
</ul> 
</div> 

<div class="overlay"></div> 
<div class="thumb"></div> 
</div>

#rotatescroll { 
width: 300px; 
height: 300px; 
margin: 0 auto; 
position: relative; 
} 
#rotatescroll .viewport{ 
width: 300px; 
height: 300px; 
position: relative; 
margin: 0 auto; 
overflow: hidden; 
} 
#rotatescroll .overview { 
width: 798px; 
position: absolute; 
list-style: none; 
margin: 0; 
padding: 0; 
left: 0; 
top: 0; 
} 
#rotatescroll .overview li { 
width: 300px; 
height: 300px; 
float: left; 
position: relative; 
} 
#rotatescroll .overlay { 
height: 300px; 
width: 300px; 
background: url(../images/bg-rotatescroll.png) no-repeat 0 0; 
position: absolute; 
left: 0; 
top: 0; 
} 
#rotatescroll .thumb { 
width: 26px; 
height: 26px; 
z-index: 200; 
background: url(../images/bg-thumb.png) no-repeat 50% 50%; 
position: absolute; 
top: 0px; 
cursor: pointer; 
left: 0px; 
} 
#rotatescroll .dot { 
background: url(../images/bg-dot2.png) no-repeat 0 0; 
display: none; 
height: 12px; 
width: 12px; 
position: absolute; 
left: 155px; 
top: 3px; 
z-index: 100; 
} 
#rotatescroll .dot span { display: none; }