var timeout
var last_big_picture = ''
var big_pictures = ["images/big_pic_01.jpg",
					"images/big_pic_02.jpg",
					"images/big_pic_03.jpg"]

function getRandom() {
   return Math.round((Math.random()*10))
}

function show_big_picture(){
	var index = getRandom()
		if ( index > (big_pictures.length - 1)){
			show_big_picture();						 
		}
		else{ 
			if(big_pictures[index] == last_big_picture){
			show_big_picture();
			}
			else{
				last_big_picture = big_pictures[index]
				document.getElementById("big_picture").src = last_big_picture
			}
		}
	}