function next_back(id_img_get){
	id_img = id_img_get;
	resta = id_img - noImg_ind;
	suma = id_img + noImg_ind;

	if ( resta >= 0 ){
		document.getElementById("btn_ind_ant").style.display = "block";
	}else{
		document.getElementById("btn_ind_ant").style.display = "none";
	}
	
	if ( suma < tam_ind ){
		document.getElementById("btn_ind_sig").style.display = "block";
	}else{
		document.getElementById("btn_ind_sig").style.display = "none";
	}
	
	if (id_img_get < 0){
		id_img = noImg_ind * Math.floor(tam_ind/noImg_ind);
	}
	if (id_img_get > tam_ind){
		id_img = 0;
	}
	max_show = id_img+noImg_ind;

	for (conta=0; conta <tam_ind; conta++){
		if (conta < 10){
			elemtn_img = "visible_00"+conta;
		}else if (conta < 100){
			elemtn_img = "visible_0"+conta;
		}else if (conta < 1000){
			elemtn_img = "visible_"+conta;
		}
		if ( (conta >= id_img) && (conta < (max_show)) ){
			document.getElementById(elemtn_img).style.display = "block";
		}else{
			document.getElementById(elemtn_img).style.display = "none";
		}
	}
}