function initImagePanels()
    {
    
        // init all panels
        document.getElementById("panel1").className = "panelVisible";
        document.getElementById("panel2").className = "panelHidden";
        document.getElementById("panel3").className = "panelHidden";
        document.getElementById("panel4").className = "panelHidden";
        document.getElementById("panel5").className = "panelHidden";  
        document.getElementById("panel6").className = "panelHidden";
        document.getElementById("panel7").className = "panelHidden";
        document.getElementById("panel8").className = "panelHidden";
        document.getElementById("panel9").className = "panelHidden";               
    }   
    
    function switchPanel(value)
    {
    
        // switch off all panels
        document.getElementById("panel1").className = "panelHidden";
        document.getElementById("panel2").className = "panelHidden";
        document.getElementById("panel3").className = "panelHidden";
        document.getElementById("panel4").className = "panelHidden";
        document.getElementById("panel5").className = "panelHidden";
        document.getElementById("panel6").className = "panelHidden";
        document.getElementById("panel7").className = "panelHidden";
        document.getElementById("panel8").className = "panelHidden";
        document.getElementById("panel9").className = "panelHidden";
        
        // turn on selected panel
    
    
        var panel = document.getElementById("panel" + value);
        
        panel.className = "panelVisible";
        
    }