$(document).ready(function()
{
    checkLeftBar();
    $(window).resize(checkLeftBar); 
});

function checkLeftBar ()
{
    var $ul = $('#sub-menu');
    
    var ul = 
    {
        top:            $ul.offset().top,
        height:         $ul.height(),
        marginTop:      Number($ul.css('marginTop').replace('px', '')),
        marginBottom:   Number($ul.css('marginBottom').replace('px', '')),
        paddingTop:     Number($ul.css('paddingTop').replace('px', '')),
        paddingBottom:  Number($ul.css('paddingBottom').replace('px', ''))
    };
    
    ul.bottom = ul.top + ul.height + ul.marginBottom + ul.marginTop + ul.paddingBottom + ul.paddingTop;

    var $bottomImage = $('#bottom-image');
        
    var bottomImage = 
    {
        top:            $bottomImage.offset().top,
        height:         $bottomImage.height(),
        marginTop:      Number($bottomImage.css('marginTop').replace('px', '')),
        marginBottom:   Number($bottomImage.css('marginBottom').replace('px', '')),
        paddingTop:     Number($bottomImage.css('paddingTop').replace('px', '')),
        paddingBottom:  Number($bottomImage.css('paddingBottom').replace('px', ''))
    };
    
    bottomImage.absoluteTop = bottomImage.top + bottomImage.marginTop + bottomImage.paddingTop;
        
    if (bottomImage.absoluteTop <= ul.bottom)
    {
        $bottomImage.css('visibility', 'hidden');
    }
    else
    {
        $bottomImage.css('visibility', 'visible');;
    }
}