function navMouseOut()
{
    this.src = this.src.replace(/b\.(jpg|gif)$/, "a.$1");
}
function navMouseOver()
{
    this.src = this.src.replace(/a\.(jpg|gif)$/, "b.$1");
}

function initNavSection(sectionToInit)
{
    var links = sectionToInit.getElementsByTagName("a");
    
    for ( i = 0; i < links.length; i++ )
    {
        var linkedImages = links[i].getElementsByTagName("img");
    
        for ( c = 0; c < linkedImages.length; c++ )
        {
            var tempImage = new Image();
            
            tempImage.src = linkedImages[c].src;
            linkedImages[c].onmouseover = navMouseOver;
            linkedImages[c].onmouseout = navMouseOut;
        }
    }
}