无法设置响应头值“内容类型”

Question

我正在尝试在继承 ASP.Net 4.5 中的 ApiController 的 valuecontroller 类中设置响应头 (Content-Type)

最终我希望在有人调用该 API 时在浏览器中呈现图像。目前它在浏览器中显示字节数组的 json 或 xml，我认为如果我正确设置了 content-Type 那么它应该可以工作。

我已经尝试过

 public byte[] Get(int id)
    {
        var context = HttpContext.Current;
        string filePath = "https://www.w3schools.com/tags/img_girl.jpg";           
        HttpContext.Current.Response.Clear();
        HttpContext.Current.Response.ClearContent();
        Byte[] b = ImageToBinary(filePath);   // Getting Byte array of a image file         
        HttpContext.Current.Response.Headers.Add("Content-Type", "image/jpeg"); // this does not works
        HttpContext.Current.Response.ContentType = "image/jpeg"; // this also does not works
        return b;
    }


public static byte[] ImageToBinary(string imagePath)
    {
        byte[] buffer = null;
        HttpWebRequest wrGETURL = (HttpWebRequest)WebRequest.Create(imagePath);
        using (System.Net.HttpWebResponse webresponse = (HttpWebResponse)wrGETURL.GetResponse())
        {
            string ct = webresponse.ContentType;
            Stream objStream = webresponse.GetResponseStream();
            using (BinaryReader breader = new BinaryReader(objStream))
            {
                buffer = breader.ReadBytes((int)webresponse.ContentLength);
            }
        }
        return buffer;
    }