abrillian

var count = $('.contr').length;
  for(var i = 1; i <= count; i++){
  var el = i-1;
  var atrib = $('img',$('.contr')[el]).attr('src');
  var bg = "url("+atrib+")";
  alert(bg)
  $('.bg').css({"background": bg})
  alert(atrib);
}