function affiche_apercu(image_url){
	document.getElementById("apercu").style.display="block";
	document.getElementById("image_apercu").src=image_url;
}

function ferme_apercu(){
	document.getElementById("apercu").style.display="none";
	document.getElementById("image_apercu").src="blank.png";
}

function taille_reelle(image_url){
	window.open(image_url);
}