How to add thumb field to Facebook video RRS feed

  • Question

  • i created desktop application that upload videos to facebook using graph.facebook and it works ok, but when i try to add "thumb" field to upload request it return error "(OAuthException - #100) (#100) Invalid image format. It should be an image file data." . 
    here my code used :note coverpath is full image path and i try to path image as bytes but the same error return.
    dynamic parameters = new ExpandoObject();
            parameters.source = new FacebookMediaObject
                                    ContentType = string.Format("video/{0}", VideoExtension.Split('.')[1]),
                                    FileName = VideoName
            parameters.title = VideoTitle;
            parameters.description = VideoTitle;           
            parameters.universal_video_id = new Guid();
            parameters.thumb = coverPath;
            parameters.published = false;
            parameters.unpublished_content_type = "DRAFT";
            dynamic uploadresult = fb.Post("/367728493684998/videos", parameters);
    Sunday, October 22, 2017 11:31 AM