jQuery(document).ready(        
    function()
    {             
        //thumbnail mouseover
        var imgThumb = ".imgThumb";        
        var originalSource='';
        
        $(imgThumb).bind("mouseenter",  
        function() 
        {                      
            var element = $(this).next('img'); 
            var srcOn = element.attr('src');
            if(srcOn!='')
            {
                originalSource= $(this).attr('src');
                $(this).attr('src', srcOn);               
            }
        });
        
        //mouseleave
        $(imgThumb).bind("mouseleave",  
        function() 
        {                      
           if(originalSource!=null && originalSource!='')
           {
            $(this).attr('src', originalSource);            
           }
        });
        
    });