// The upcast override creates a figure wrapper and put all the stuff inside it:

CKEDITOR.plugins.add( 'drupal_image2', {
    requires: 'image2',

    beforeInit: function (editor) {

      editor.on('widgetDefinition', function (event) {
        var widgetDefinition = event.data;
        if (widgetDefinition.name !== 'image') {
          return;
        }

        widgetDefinition.upcast = function (element, data) {
          if (element.name !== 'img') {
            return;
          }

          var retElement = element;

          if (element.name !== 'figure') {
            var figure = new CKEDITOR.htmlParser.element('figure');
            element.replaceWith(figure);
            figure.add(element);
            retElement = figure;
          }

          return retElement;
        };

      });

    },

});


// below function is used because I wanted to alter the dialog and is not
// mandatory for the 'figure' wrapper above.

CKEDITOR.on( 'dialogDefinition', function( ev ) {
    var dialogName = ev.data.name;
    var dialogDefinition = ev.data.definition;
    if ( dialogName == 'image2' ) {

      dialogDefinition.onShow = function () {
        // this.getContentElement("info","src").getElement().hide(); 
      }

    }
});