Generating a List of Random Background Images with a Sass Loop

// I wanted to use this method (http://codepen.io/jcasabona/pen/fKgCA) of displaying random background images with Sass, but I didn't want to type out each image file name, so instead I used a loop:

$random_images_path: "../../../uploads/";
$imagesarray: ('');
@for $i from 1 through 40 {
  $value: $random_images_path + "/sitename" + $i + ".jpg";
  $imagesarray: append($imagesarray, $value);
}

$img: nth($imagesarray, random(length($imagesarray) -1));

#content {
  background: url($img) no-repeat center center;
  background-size: cover;
  }