#global_temporaire {
position:absolute;
left: 50%;
top: 50%;
width: 284px;
margin-left: -142px;
height: 284px;
margin-top: -142px;
}

#global {
position:absolute;
left: 50%;
top: 50%;
width: 284px;
margin-left: -142px;
height: 284px;
margin-top: -142px;
background-image:url(../images/guy-vivien-photographe.gif);
background-repeat:no-repeat;
}