use the below code for the shadow effect. better you use css than images for shadows effects. because css is easy to create,edit and load fastly. images are not easy to create,edit and to load fastly compared with the css.
<div class="box effect2">
<h3>Effect 2</h3>
</div>
.box h3{
text-align:center;
position:relative;
top:80px;
}
.box {
width:70%;
height:200px;
background:#FFF;
margin:40px auto;
}
/*==================================================
* Effect 2
* ===============================================*/
.effect2
{
position: relative;
}
.effect2:before, .effect2:after
{
z-index: -1;
position: absolute;
content: "";
bottom: 15px;
left: 10px;
width: 50%;
top: 80%;
max-width:300px;
background: #777;
box-shadow: 0 15px 10px #777;
transform: rotate(-3deg);
}
.effect2:after
{
transform: rotate(3deg);
right: 10px;
left: auto;
}