使用iTextSharp v4.1.2，如何将图像添加到标题？

Question

我可以在iTextSharp v4.1.2中添加文本标题但是如何添加图像而不是文本？我目前正在使用文本标题，但我想用图像替换它。

    ' Create a Document object
    Dim doc As Document = New Document(PageSize.LETTER)
    doc.SetMargins(pageMarginLeft, pageMarginRight, pageMarginTopBottom, pageMarginTopBottom)

    ' Create a new PdfWriter object, specifying the output stream
    Dim writer As PdfWriter = PdfWriter.GetInstance(doc, HttpContext.Current.Response.OutputStream)

    ' Set header and footer
    Dim headerFont As iTextSharp.text.Font = FontFactory.GetFont("Arial", 12, iTextSharp.text.Color.BLUE)
    Dim header As New HeaderFooter(New Paragraph("VOLUNTEER MASTER SCHEDULE", headerFont), False)

    Dim footerFont As iTextSharp.text.Font = FontFactory.GetFont("Arial", 8, iTextSharp.text.Color.BLACK)
    Dim footer As New HeaderFooter(New Phrase("Page: ", footerFont), True)
    doc.Header = header
    doc.Footer = footer

    ' Open the Document for writing
    doc.Open()