CSS3实现的图片加载动画效果

<ul class="grid effect-4" id="grid">
    <li><a href="http://drbl.in/fWMM"><img src="images/1.jpg"></a></li>
    <li><a href="http://drbl.in/fWPV"><img src="images/2.jpg"></a></li>
    <li><a href="http://drbl.in/fWMT"><img src="images/3.jpg"></a></li>
    <li><a href="http://drbl.in/fQdt"><img src="images/4.png"></a></li>
    <!-- ... -->
</ul> 

    /* Effect 4: fall perspective */
    .grid.effect-4 {
    perspective: 1300px;
    }
    .grid.effect-4 li {
    transform-style: preserve-3d;
    }
    .grid.effect-4 li.animate {
    transform: translateZ(400px) translateY(300px) rotateX(-90deg);
    animation: fallPerspective .8s ease-in-out forwards;
    }
    @keyframes fallPerspective {
    100% { transform: translateZ(0px) translateY(0px) rotateX(0deg); opacity: 1; }
    }