Easy image rollover without effects

rollover.htm

<img src="http://dummyimage.com/254x403/ccc/000.jpg&amp;text=254x403+-+Produkt" data-hover="http://dummyimage.com/254x403/999/000.jpg&amp;text=254x403+-+Produkt" alt="" />

rollover.js

$('img[data-hover]').each(
    function() {
        var img = $(this);
        
        // preload hover-image
        $('<img />').attr( 'src', img.attr('data-hover') );
        
        // rollover
        img.on(
            'mouseenter mouseleave',
            function() {
                var $this = $(this),
                    orig = $this.attr('src');
                
                $this.attr({
                    'src': $this.attr('data-hover'),
                    'data-hover': orig
                });
            }
        );
    }
);