Tween1100相当の Thumbnail.vb にDM添付画像をサムネイル表示するコードを書いたら多分こんな感じ

gistfile1.vb

    ' コンパイルも通してない適当コード
    ' 参考: https://github.com/opentween/OpenTween/blob/456c6d3b30a6731b1b9dde151da4a4d1752fad5f/OpenTween/Thumbnail/Services/TonTwitterCom.cs

    Private Function TonTwitterCom_GetUrl(ByVal args As GetUrlArgs) As Boolean
        Dim url As String = If(String.IsNullOrEmpty(args.extended), args.url, args.extended)
        Return url.StartsWith("https://ton.twitter.com/1.1/ton/data/")
    End Function
    
    Private Function TonTwitterCom_CreateImage(ByVal args As CreateImageArgs) As Boolean
        Dim oauth As New HttpOAuthApiProxy()
        oauth.Initialize(<<<ConsumerKey>>>, <<<ConsumerSecret>>>,
                     Owner.tw.AccessToken, Owner.tw.AccessTokenSecret, "", "")
        
        Dim responseStream As Stream = Nothing
        Dim userAgent As String = My.Application.Info.AssemblyName & "/" & MyCommon.fileVersion & " (compatible; MSIE 10.0)"
        Dim statusCode As HttpStatusCode = oauth.GetContent("GET", New Uri(args.url.Value), Nothing, response, userAgent)

        Using responseStream
            If statusCode = HttpStatusCode.OK Then
                Dim img As Bitmap
                Try
                    img = New Bitmap(responseStream)
                    args.pics.Add(New KeyValuePair(Of String, Image)(args.url.Key, img))
                    args.tooltipText.Add(New KeyValuePair(Of String, String)(args.url.Key, ""))
                    Return True
                Catch ex As Exception
                    If img IsNot Nothing Then
                        img.Dispose()
                    End If
                    args.errmsg = ex.ToString()
                End Try
            Else
                args.errmsg = statusCode.ToString()
            End If
        End Using
        
        Return False
    End Function