Argument 1 passed must be an instance of App\Request, instance of Illuminate\Http\Request given

I have created a method in my User model to upload a poster (with intervention)for the user:

/**
* Store user's poster.
*/
public static function storePoster(Request $request) 
{
    if($request->hasFile('posterUpload')){

        $poster = $request->file('posterUpload');

        $filename = time() . '.'. $poster->getClientOriginalExtension();

        Image::make($poster)->resize(356,265)->save(public_path('/uploads/posters/'.$filename));

        $check = Setting_user::where([
                ['user_id', '=' ,Auth::user()->id],
                ['setting_id','=', 2],
        ])->first();

        if(!$check)
        {
            $setting = new Setting_user();
            $setting->user_id = Auth::user()->id;
            $setting->setting_id = 2;
            $setting->value = $filename;
            $setting->save();
            return back();
        }

        $check->value = $filename;
        $check->update();
        return back();

    }

}

In my UserController I have another method which call the static method created in the User model:

/**
* Store user's poster.
*/
public function poster(Request $request) 
{
     User::storePoster($request);

}

This is my route:

Route::post('/user-profile/store/poster', 'UserController@poster');

And this is the error I get when I navigate to "/user-profile/store/poster" :

Argument 1 passed to App\User::storePoster() must be an instance of App\Request, instance of Illuminate\Http\Request given, called in C:\xampp\htdocs\laravel\laravel-paper-dashboard\app\Http\Controllers\UserController.php on line 29 and defined

Although if I move all the logic from the model and put it in my UserController it works fine. Any idea why?

Thanks in advance.