src/ImageResponse.php
public function withHeader($name, $value)
    {
        $response = clone $this;

        if ($this->isAllowedHeader($name = strtolower($name))) {
            $response->headers[$name] = $this->getHeaderValue($value);
        }

        return $response;
    }
public function withHeader($name, $value)
    {
        $response = clone $this;

        if ($this->isAllowedHeader($name = strtolower($name))) {
            $response->headers[$name] = $this->getHeaderValue($value);
        }

        return $response;
    }
{@inheritdoc}