Maybe like this?
```php
// Send the correct HTTP header
Request::current()->response()
	->headers('Content-Type', 'image/'.$this->image_type)
	->headers('Cache-Control', 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0')
	->headers('Pragma', 'no-cache')
	->headers('Connection', 'close');
```