readonly class UploadImageDTO
{
  public function __construct(
    public string $title,
    public string $description,
    // Add assertions about mime type and size, if possible.
    public UploadedFile $file,
  ) {}
}

class SomeController
{
  public function uploadImage(
    #[MapRequestPayload] UploadImageDTO $requestData
  ): Response
  {
    // $requestData->file is guaranteed to be an UploadedFile
  }
}