// If you wanted to make the icons partially transparent all the time but on mouse over make them 0% transparent, you can do so like so:
CSS: #sidebar img.icon{ filter:alpha(opacity=50); -moz-opacity: 0.5; opacity: 0.5; } #sidebar img.icon:hover{ filter:alpha(opacity=100); -moz-opacity:1.0; opacity:1.0; }