title: How to set ContentType for unknown image extensions?
body: <p>I have a service returning an image stream to be displayed in UI. How do I set the ContentType value for this as I do not know what the image type will be? It can be image/jpeg, image/png etc.</p>
  
  <pre><code>fileContent.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("inline")
                      {
                          FileName = fileName
                      };
                      fileContent.Content.Headers.ContentType = new MediaTypeHeaderValue(??);
  </code></pre>