function change_photo(increment) {
				
				photo = photo + increment;

				if(photo > nb_photos)
					photo = 1;
					
				if(photo <= 0)
					photo = nb_photos;
						
				if(nb_photos > 0)
					document.getElementById("img").src = "photos/"+montab[photo];
			}
		
		
			function zoom(largeur,hauteur,options) {
				var top = (screen.height-hauteur)/2;
				var left = (screen.width-largeur)/2;
				window.open("zoom.php?id="+id_annonce+"&num_photo="+photo,"","top="+top+",left="+left+",width="+largeur+",height="+hauteur+","+options);
			}
		
			function impression() {
				window.open("impression.php?id="+id_annonce);
			}