table {
    table-layout: auto!important;
}
a.pk{
background:transparent url('../images/pkey.jpg') center no-repeat;
display:block;
height:25px;
text-indent:-9999px;
width:25px;
}

a.fk{
background:transparent url('../images/fkey.png') center no-repeat;
display:block;
height:25px;
text-indent:-9999px;
width:25px;
}

a.index{
background:transparent url('../images/index.png') center no-repeat;
display:block;
height:25px;
text-indent:-9999px;
width:25px;
}