iTextSharp填充Pdf表单图像字段

我用Acrobat DC 2015创建了一个pdf表单。上面有一个图像字段。我成功地填充了文本字段。但我不知道如何填充图像场。你能帮我吗?

    private static void FillPdfForm()
    {
        // Original File
        const string pdfTemplate = @"pdf\form.pdf";
        // New file which will be created after fillin PDF
        var newFile = @"pdf\FilledCV.PDF";
        var pdfReader = new PdfReader(pdfTemplate);
        var pdfStamper = new PdfStamper(pdfReader, new FileStream(
            newFile, FileMode.Create));
        var pdfFormFields = pdfStamper.AcroFields;

        // So one of our fields in PDF is FullName I am filling it with my full name
        pdfFormFields.SetFieldProperty("01", "textsize", 8f, null);
        pdfFormFields.SetField("01", "Example");

        // flatten the form to remove editting options, set it to false
        // to leave the form open to subsequent manual edits

        foreach (var de in pdfReader.AcroFields.Fields)
        {
            pdfFormFields.SetFieldProperty(de.Key.ToString(),
                                       "setfflags",
                                        PdfFormField.FF_READ_ONLY,
                                        null);
        }

        pdfStamper.FormFlattening = false;
        pdfStamper.FormFlattening = false;
        pdfStamper.Close();
    }