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
std::string lower = base::ToLowerASCII(text);
    if (lower == "cancel")
      return GTK_STOCK_CANCEL;
    else if (lower == "no")
      return GTK_STOCK_NO;
    else if (lower == "ok")
      return GTK_STOCK_OK;
    else if (lower == "yes")
      return GTK_STOCK_YES;
    else
      return text.c_str();
  }
  void Show() {
    gtk_widget_show_all(dialog_);
    
    
    int time = views::X11DesktopHandler::get()->wm_user_time_ms();
    gtk_window_present_with_time(GTK_WINDOW(dialog_), time);
  }
  int RunSynchronous() {
    gtk_window_set_modal(GTK_WINDOW(dialog_), TRUE);
    Show();
    int response = gtk_dialog_run(GTK_DIALOG(dialog_));
    if (response < 0)
      return cancel_id_;
    else
      return response;
  }
  void RunAsynchronous(const MessageBoxCallback& callback) {