gistfile1.js

// The JSON is provided by the server-side. It's a json string stored in the db.
var init_slides = JSON.parse('[{"url":"..."}]');

// When the form is submited, we're serializing the files and storing them in a hidden input field.
$('.submit-form').submit(function() {
  	$("#slides").val(JSON.stringify(uploaded_media_fpfiles));
});

// When the page is loaded for the first time, we're faking a file update using the fpfiles already saved.
uploaded_media(init_slides);