this.iPreview = function(){
    /* CONFIG */
        xOffset = 10;
        yOffset = 20;
        // these 2 variable determine popup's distance from the cursor
        // you might want to adjust to get the right result
    /* END CONFIG */

    $$('a.ipreview').each(function(elm){
        
        elm.observe('mouseover',function(e){
            
            mouseX = Event.pointerX(e);
            mouseY = Event.pointerY(e);

            $(document.body).insert("<p id='ipreview'><img src='"+ this.rel +"' /></p>");

            $("ipreview").setStyle({position: "absolute"});
            $("ipreview").setStyle({padding: "5px"});
            $("ipreview").setStyle({zIndex: "9999"});
            $("ipreview").setStyle({border: "1px solid #bbb"});
            $("ipreview").setStyle({background: "#ffffff"});
            $("ipreview").setStyle({left: (mouseX + xOffset) + "px"});
            $("ipreview").setStyle({top: (mouseY + yOffset) + "px"});
            $("ipreview").appear();
        });
        
        elm.observe('mouseout',function(){
                $("ipreview").remove();
        });
        
        elm.observe('mousemove', function(e){
        
             mouseX = Event.pointerX(e);
             mouseY = Event.pointerY(e);
             
             $("ipreview").setStyle({left: (mouseX + xOffset) + "px"});
             $("ipreview").setStyle({top: (mouseY + yOffset) + "px"});

        });
    });

};


Event.observe(window, 'load', function() {
    iPreview();
});