I'm using the Facebook C# SDK 5.0.25. I'm attempting to upload a photo to my wall, and I've been following the example given in the "Samples/Facebook/Dynamic/GraphApi.cs" document, but I'm receiving the following error:
"(OAuthException) An access token is required to request this resource"

I've tried several different solutions, but the closest I've come is the below code, which gives me the above error.

```
    public static bool PostPNG(string UserID)
    {
        // sample usage: UploadPictureToWall(accessToken, @"C:\Users\Public\Pictures\Sample Pictures\Penguins.jpg");
        string filePath = @"C:\Users\Public\Pictures\Sample Pictures\Penguins.jpg";

        var mediaObject = new FacebookMediaObject
        {
            FileName = System.IO.Path.GetFileName(filePath),
            ContentType = "image/jpg"
        };

        mediaObject.SetValue(System.IO.File.ReadAllBytes(filePath));

        //try
        //{
            var client = new FacebookClient(FBconstants.APP_ID, FBconstants.APP_SECRET);
            string access_token = client.AccessToken;
            client = new FacebookClient(access_token);

            dynamic parameters = new ExpandoObject();
            parameters.source = mediaObject;
            parameters.message = "photo?";
            parameters.access_token = access_token;

            dynamic result = client.Post(UserID+"/photos", parameters);

            PostDelete(result.id);

            return true;
        //}
        //catch (FacebookApiException ex)
        //{
        //    return false;
        //}
    }

```

I also found that if switched the Post command to post to "/feed" then the command executes, but without the photo.
Any suggestions would be greately appreciated.