aviaryCustomSave.js

var editor = new Aviary.Feather({
  // config
  onSaveButtonClicked: function() {
    // 1. start custom spinner and disable editor
    editor.getImageData(function(data) { // `data` contains a base64 encoding of the image
      // 2. POST `data` to your own server
      // 3. stop custom spinner and enable or close the editor
    });
    return false; // prevents editor from following defautl save behavior
  }
});