#caso-uno {
    background-image: url('images/home/intro01.jpg');
}
#caso-dos {
    background-image: url('images/home/intro02.jpg');
}
#caso-tres {
    background-image: url('images/home/intro03.jpg');
}
a.descargar-caso {
    left:389px;
    width:141px;
    background-image: url('images/home/botdescar24.gif');
}
a.mas-caso {
    left:544px;
    width:128px;
    background-image: url('images/home/botvermas24.gif');
}