orbit-basic/vendor/built_in_modules/gallery/app/assets/javascripts/file-upload/main.js

//https://github.com/blueimp/jQuery-File-Upload
$(function () {
    'use strict';
    // Initialize the jQuery File Upload widget:
    $('#fileupload').fileupload({
        maxFileSize: 5000000,
        acceptFileTypes: /(\.|\/)(gif|jpe?g|png)$/i,
        dropZone: $('#dropzone'),
        headers:{
            'X-CSRF-Token': $('meta[name="csrf-token"]').attr("content")
        }
    });
});