Whilst looking for a solution some time back, I found a similar script to the below, which after some tweaking I got working for me.

It handles two images, that almost always default to "off", where the mouse is off the image (image-example_off.jpg), and the occasional "on", where for the times the mouse is hovered, the required alternative image (image-example_on.jpg) is displayed.

<script type="text/javascript">        
    $(document).ready(function() {        
        $("img", this).hover(swapImageIn, swapImageOut);

        function swapImageIn(e) {
            this.src = this.src.replace("_off", "_on");
        }
        function swapImageOut (e) {
            this.src = this.src.replace("_on", "_off");
        }
    });
</script>

If the solution you are looking for is for an animated button, then the best you can do to improve in performance is the combination of sprites and CSS. A sprite is a huge image that contains all the images from your site (header, logo, buttons, and all decorations you have). Each image you have uses an HTTP request, and the more HTTP requests the more time it will take to load.

.buttonClass {
    width: 25px;
    height: 25px;
    background: url(Sprite.gif) -40px -500px;
}
.buttonClass:hover {
    width: 25px;
    height: 25px;
    background: url(Sprite.gif) -40px -525px;
}

The 0px 0px coordinates will be the left upper corner from your sprites.

But if you are developing some photo album with Ajax or something like that, then JavaScript (or any framework) is the best.

Have fun!

I was hoping for an über one liner like:

$("img.screenshot").attr("src", $(this).replace("foo", "bar"));

我知道您在问使用jQuery，但是在使用CSS关闭JavaScript的浏览器中也可以达到相同的效果：

#element {
    width: 100px; /* width of image */
    height: 200px; /* height of image */
    background-image: url(/path/to/image.jpg);
}

#element:hover {
    background-image: url(/path/to/other_image.jpg);
}

有一个较长的描述在这里

然而，更好的是使用精灵：simple-css-image-rollover