Resposta SOPT

Pergunta SOPT: http://pt.stackoverflow.com/q/39078/223

by Salustiano Silva

HTML

<div class="bg">        
    <div class="logo"></div>
    <form>FORM</form>
</div>

CSS

bg{
    background-image: url("../imagens/bg.jpg");
    background-repeat: no-repeat;
    background-position: center;
    width: 100%;
    height: 1138px;
}
.logo {
    background-color:red;
    width: 140px;
    height: 101px;
    margin-left: -70px;
    left: 50%;
    position: absolute;
}