I've created a set of custom validation rules in my Laravel application. I first created a `validators.php` file which is in the `App\Http` directory:

```
/**
 * Require a certain number of parameters to be present.
 *
 * @param  int     $count
 * @param  array   $parameters
 * @param  string  $rule
 * @return void
 * @throws \InvalidArgumentException
 */

    function requireParameterCount($count, $parameters, $rule) {

        if (count($parameters) < $count):
            throw new InvalidArgumentException("Validation rule $rule requires at least $count parameters.");
        endif;

    }

/**
 * Validate the width of an image is less than the maximum value.
 *
 * @param  string  $attribute
 * @param  mixed   $value
 * @param  array   $parameters
 * @return bool
 */

    $validator->extend('image_width_max', function ($attribute, $value, $parameters) {

        requireParameterCount(1, $parameters, 'image_width_max');

        list($width, $height) = getimagesize($value);

        if ($width >= $parameters[0]):
            return false;
        endif;

        return true;

    });

```

I'm then adding including this in my `AppServiceProvider.php` file (while also adding `use Illuminate\Validation\Factory;` at the top of this file):

```
public function boot(Factory $validator) {

    require_once app_path('Http/validators.php');

}

```

Then in my form request file, I can call the custom validation rule, like so:

```
$rules = [
    'image' => 'required|image|image_width:50,800',
];

```

Then in the Laravel `validation.php` file located in the `resources/lang/en` directory, I'm adding another key/value to the array to display an error message if the validation returns false and fails, like so:

```
'image_width' => 'The :attribute width must be between :min and :max pixels.',

```

Everything works fine, it checks the image correctly, displays the error message if it fails, but I'm not sure how to replace `:min` and `:max` with the values declared in the form request file (50,800), the same way `:attribute` is replaced with the forms field name. So currently it displays:

`The image width must be between :min and :max pixels.`

Whereas I want it to display like this

`The image width must be between 50 and 800 pixels.`

I've seen some `replace*` functions in the master `Validator.php` file `(vendor/laravel/framework/src/Illumiate/Validation/)`, but I can't quite seem to figure out how to get it to work with my own custom validation rule.