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
#include "atom/browser/ui/message_box.h"
#include "atom/browser/browser.h"
#include "atom/browser/native_window.h"
#include "base/callback.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/browser/ui/libgtk2ui/gtk2_signal.h"
#include "chrome/browser/ui/libgtk2ui/gtk2_util.h"
#include "chrome/browser/ui/libgtk2ui/skia_utils_gtk2.h"
#include "ui/views/widget/desktop_aura/x11_desktop_handler.h"
#define ANSI_FOREGROUND_RED   "\x1b[31m"
#define ANSI_FOREGROUND_BLACK "\x1b[30m"
#define ANSI_TEXT_BOLD        "\x1b[1m"
#define ANSI_BACKGROUND_GRAY  "\x1b[47m"
#define ANSI_RESET            "\x1b[0m"
namespace atom {
namespace {
class GtkMessageBox {