Q:

Fade in background image on load

I want to load one of the random background image by using jquery. Below is the script I am using and it shows random background on refresh but without fadeIn effect. How can I create fadeIn effect onload. Note: I don't want to cycle random images.
$(document).ready(function() {
  var images = ['01.jpg', '02.jpg', '03.jpg', '04.jpg', '05.jpg', '06.jpg', '07.jpg', '08.jpg', '09.jpg', '10.jpg'];

  $('.about').css({'background-image': 'url(../img/bg/' + images[Math.floor(Math.random() * images.length)] + ')'});
  ('.about').fadeIn(1000);
});

A:

$(document).ready(function() {
  var images = ['http://funmozar.com/wp-content/uploads/2014/09/Beautiful-Yellow-Birds-06.jpg', 'http://petblaster.com/images/Birdwall.jpg', 'http://www.nscblog.com/wp-content/uploads/2014/04/birds-314989.jpg'];

  var url = images[Math.floor(Math.random() * images.length)];
  var img = new Image();
  img.onload = function(){
    $('.about').css({'background-image': 'url('+url+')', 'background-size' : 'contain'});
    $('.about').fadeIn(1000);
  }
  img.src = url;
  
  
});
.about{
  width: 400px;
  height: 400px;
  display: none;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<div class="about"></div>

This will preload the image using new Image. An onload is attached. When he onload fires it will set the background to the .about div and fade it in.
I've changed the urls to actually show some results.

