Can you use different icon images for each list element within an unordered list?

I'm not an advanced user of CSS, but I have a decent working knowledge i suppose. I'm tryin to make an unordered list that uses different icons for each list element. I would also like the background colour of the list element to change upon hover.

Is there a way to do this through CSS, or would you just include the icon image within the list element (like below)?

<li><img src="voters.jpg"><a href="voters.html">Voters</a></li>

Using the list-style-image on the ul level makes all of the icons the same, and I haven't been able to figure out another way. Most examples I've found teach you how to use images in a list, but only if the bulleted images are the same. I'm definitely open to suggestions and improvements on the way I'm trying to do this.

thanks

<div class="content-nav">
  <ul>
    <li class="instructions"><a href="instructions.html">Instructions</a></li>
    <li class="voters"><a href="voters.html">Voters</a></li>
  </ul>
</div>

.content-nav {
    font-size:12px;
    width:160px;
    z-index:0;
}

.content-nav ul {
    padding:0 20px;
    margin:30px 0;
}

.content-nav li {
    padding:5px;
    margin:5px 5px;
}

.content-nav li a {
    color:#666;
    text-decoration:none;
}

.content-nav li.voters a {
    background:#FFF;
    color:#666;
    text-decoration:none;
    list-style-image:url(images/voters.jpg);
}

.content-nav li.voters a:hover {
    background:#0CF;
    color:#000;
}

.content-nav li.instructions a {
    background:#FFF;
    color:#666;
    text-decoration:none;
    list-style-image:url(images/voters.jpg);
}

.content-nav li.instructions a:hover {
    background:#0CF;
    color:#000;
}