Laravel Regex Validation (text should end up with .jpg or .png)

I have a laravel validation rule something like this

public function rules(){
   return [
            'title' => 'required|max:100',
            'featured_image' => 'required|max:100|regex:(\d)+.(?:jpe?g|png|gif)',

        ];
}

I have a txt field where i dynamically add an image name, something like this (8123123123.jpg OR 234234234.png). If the text field doesn't have this pattern i want to show an error.

Now this regex does work in http://regexr.com/ but in laravel it doesn't. So basically it should look for digits as file name and should end with .jpg or .png

Any help is appreciated

via Chebli Mohamed