Images in dropdown list

You could use jQuery Image Dropdown:

http://marghoobsuleman.com/jquery-image-dropdown

_{(source: marghoobsuleman.com)}

<script language="javascript">    
$(document).ready(function(e) {
    try {
        // target some ids
        MSDropDown.init("#combo1, #combo2");
        //by wild card
        MSDropDown.init("#divid select");
        //or 
        MSDropDown.init("#formid select");
    } catch(e) {
    alert(e);
    }
})
</script>

Dropdownlist with images

http://www.dotnetspeaks.com/DisplayArticle.aspx?ID=90

Try this, it's one of the best solution.... and easiest
http://www.obout.com/combobox/icons/aspnet_icons_database.aspx

I haven't tried to use this JQuery Combo-Box, but from the screenshot, it looks like the items in the combo box can include an image in it. Maybe you could research more regarding this.