Mine

EAPI int
e_widget_preview_thumb_set(Evas_Object *obj, const char *file, const char *key, int w, int h)
{
   E_Widget_Data *wd;

   wd = e_widget_data_get(obj);

   if (wd->img)
      evas_object_del(wd->img);

   wd->img = e_thumb_icon_add(evas_object_evas_get(obj));
   e_thumb_icon_file_set(wd->img, file, key);
   e_thumb_icon_size_set(wd->img, w, h);
   e_thumb_icon_begin(wd->img);
   evas_object_smart_callback_add(wd->img, "e_thumb_gen", _e_wid_preview_thumb_gen, wd);
   edje_object_part_swallow(wd->o_frame, "item", wd->img);
   evas_object_show(wd->img);
   return 1;
}

static void
_e_wid_preview_thumb_gen(void *data, Evas_Object *obj, void *event_info)
{
   Evas_Coord w, h;
   E_Widget_Data *wd;
   wd = data;

   evas_object_geometry_get(wd->img, 0, 0, &w, &h);
   evas_object_resize(wd->o_frame, w, h);
}