How to read image metadata when source is http

Question

I have no problem getting to the metadata is the file is local, but if my reference is a more general http uri -- that's the problem. Here is my test code:

        String s = "http://myserver/MediaStore/pic1.jpg";
        //String s = "c:\\MediaStore\\pic1.jpg";  <==== This works
        Uri u = new Uri(s, UriKind.RelativeOrAbsolute);
        BitmapDecoder bd = BitmapDecoder.Create(u, BitmapCreateOptions.None, BitmapCacheOption.None);
        BitmapMetadata bm = (BitmapMetadata)bd.Frames[0].Metadata;
        String manufacturer = bm.CameraManufacturer;
        // ... then access more fields