var num=0;

function arriere(){
	if (num == 0)
		 num = nbphoto-1
	else
		 num--;
		eval('document.pics.src=Photo'+num+'.src');
}

function avant()
{
	if (num == nbphoto-1)
		 num = 0
	else
		 num++;
	
	eval('document.pics.src=Photo'+num+'.src');
}