protected function getDefaultThumbOptions($override = [])
    {
        $defaultOptions = [
            'fit' => 'contain',
            'width' => 0,
            'height' => 0,
            'quality' => 90,
            'sharpen' => 0,
            'extension' => 'auto',
        ];

        if (!is_array($override))
            $override = ['fit' => $override];

        $options = array_merge($defaultOptions, $override);

        if (strtolower($options['extension']) == 'auto')
            $options['extension'] = strtolower($this->getExtension());

        return $options;
    }