With the following code:

``` js
app.on('ready', () => {
    electron.dialog.showMessageBox({
        message: 'Lorem ipsum',
        buttons: [],
        icon: path.join(__dirname, 'Icon.png')
    });
});
```

_The icon is 1024x1024 pixels._

This is what I get on Linux:

<img width="1159" alt="screen shot 2016-05-10 at 18 15 07" src="https://cloud.githubusercontent.com/assets/170270/15144697/4f4d9c1a-16db-11e6-9fd8-a52534a4ae76.png">

The icon is correctly resized on OS X:

<img width="438" alt="screen shot 2016-05-10 at 18 16 03" src="https://cloud.githubusercontent.com/assets/170270/15144718/6ecbac58-16db-11e6-95cc-8c312bcecb2e.png">

And Windows:

<img width="361" alt="screen shot 2016-05-10 at 18 15 37" src="https://cloud.githubusercontent.com/assets/170270/15144721/7432fbe2-16db-11e6-8322-5980def359e9.png">
## 

The documentation for the `icon` option should also document the recommended minimum size for the icon.
## 
- Electron version: 0.37.8
- Operating system: Ubuntu 14.04

atom/browser/ui/message_box_gtk.cc
GetMessageType(type),  
        GTK_BUTTONS_NONE,  
        "%s", message.c_str());
    if (!detail.empty())
      gtk_message_dialog_format_secondary_text(
          GTK_MESSAGE_DIALOG(dialog_), "%s", detail.c_str());
    if (!title.empty())
      gtk_window_set_title(GTK_WINDOW(dialog_), title.c_str());
    
    if (!icon.isNull()) {
      GdkPixbuf* pixbuf = libgtk2ui::GdkPixbufFromSkBitmap(*icon.bitmap());
      GtkWidget* image = gtk_image_new_from_pixbuf(pixbuf);
      gtk_message_dialog_set_image(GTK_MESSAGE_DIALOG(dialog_), image);
      gtk_widget_show(image);
      g_object_unref(pixbuf);
    }
    
    for (size_t i = 0; i < buttons.size(); ++i) {
      GtkWidget* button = gtk_dialog_add_button(
          GTK_DIALOG(dialog_), TranslateToStock(i, buttons[i]), i);
      if (static_cast<int>(i) == default_id)
        gtk_widget_grab_focus(button);
    }
    
    if (parent_window) {
      gfx::NativeWindow window = parent_window->GetNativeWindow();
      libgtk2ui::SetGtkTransientForAura(dialog_, window);
    }
  }
  ~GtkMessageBox() {