function NewWindow(mypage, myname, w, h, scroll) 
{
    var winl = (screen.width - w) / 2;
    var wint = (screen.height - h) / 2;
    
	winprops = 'height='+h+',width='+w+',top='+wint+',left='+winl+',scrollbars='+scroll+',resizable'
	
	window.opener = this.window;
	window.open(mypage, myname, winprops);  
}

function ChangeImage( curr_img, new_src )
{
    // Set this to correct path to images folder
    var root_src = "./images/";
    
    new_src = root_src + new_src;
    var img_id = document.getElementById( curr_img );
    img_id.src = new_src;
}