图片预加载

http://www.neoease.com/lazy-load-jquery-plugin-delay-load-image/

<img class='lazy' data-original="images/29.jpg" src="images/pixel.gif" alt="" /><br/>

$(function (){
      $("img.lazy").show().lazyload({threshold:200});
})

.lazy{
     display: none;
}

http://www.neoease.com/lazy-load-jquery-plugin-delay-load-image/