How to vertical align image inside div

Question

Possible Duplicate:
How to properly vertically align an image

Image size changes but the div size is fixed

These are CSS but not working. Is it possible to achieve this without using background feature of CSS.

This is CSS class which image is inserted in.

    .PI
{
    top: 25px;
    position: absolute;
    width: 239px;
    height: 120px;
    line-height:120px;
    text-align: center;
    left:-2px;
      border-top: 1px solid #f7f7f7;
   background: #b5aeb1;
   background: -webkit-gradient(linear, left top, left bottom, from(#d9d9d9), to(#b5aeb1));
   background: -webkit-linear-gradient(top, #d9d9d9, #b5aeb1);
   background: -moz-linear-gradient(top, #d9d9d9, #b5aeb1);
   background: -ms-linear-gradient(top, #d9d9d9, #b5aeb1);
   background: -o-linear-gradient(top, #d9d9d9, #b5aeb1);
   -webkit-border-radius: 8px;
   -moz-border-radius: 8px;
   border-radius: 8px;
   -webkit-box-shadow: rgba(0,0,0,1) 0 1px 0;
   -moz-box-shadow: rgba(0,0,0,1) 0 1px 0;
   box-shadow: rgba(0,0,0,1) 0 1px 0;
   text-decoration: none;
   vertical-align: middle;  
}

.PI img
{
margin: auto;
vertical-align: middle;  
}