Gravity Forms full page spinner

gform_spinner_style.css

img.gform_ajax_spinner {
  position: fixed !important;
  z-index: 999999;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  display: block !important;
  overflow: hidden !important;
  width: 100% !important;
  height: 100% !important;
  background-color: rgba(0,0,0);
  /* fall back */
  background-color: rgba(0,0,0,0.7);
  url('/wp-content/uploads/.../preloading.gif'); /* fallback GIF spinner */
  /* awesome svg loaders from http://samherbert.net/svg-loaders/ */
  background-image: linear-gradient(transparent,transparent), url('/wp-content/uploads/.../pulse.svg'); /* SVG spinner */
  background-repeat: no-repeat;
  background-size: 60px 60px;
  background-position: center center;
}

gforms_custom_loading_spinner.php

<?php
add_filter("gform_ajax_spinner_url", "transparent_spinner_url", 10, 2);
function transparent_spinner_url( $image_src, $form ){
  // locally load https://commons.wikimedia.org/wiki/File:Transparent.gif
  return '/wp-content/uploads/.../transparent.gif';
}

wordpress_allow_svg_upload.php

<?php
add_filter('upload_mimes', 'inject_svg_mime_types');
function inject_svg_mime_types($mimes) {
  $mimes['svg'] = 'image/svg+xml';
  return $mimes;
}