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
MessageBoxType type,
                   const std::vector<std::string>& buttons,
                   int default_id,
                   int cancel_id,
                   int options,
                   const std::string& title,
                   const std::string& message,
                   const std::string& detail,
                   const gfx::ImageSkia& icon) {
  return GtkMessageBox(parent, type, buttons, default_id, cancel_id,
                       title, message, detail, icon).RunSynchronous();
}
void ShowMessageBox(NativeWindow* parent,
                    MessageBoxType type,
                    const std::vector<std::string>& buttons,
                    int default_id,
                    int cancel_id,
                    int options,
                    const std::string& title,
                    const std::string& message,
                    const std::string& detail,
                    const gfx::ImageSkia& icon,
                    const MessageBoxCallback& callback) {
  (new GtkMessageBox(parent, type, buttons, default_id, cancel_id,
                     title, message, detail, icon))->RunAsynchronous(callback);
}
void ShowErrorBox(const base::string16& title, const base::string16& content) {