using (var chartimage = new MemoryStream())
            {

                chartCentersByYear.SaveImage(chartimage, ChartImageFormat.Png);
                using (var imageSys = System.Drawing.Image.FromStream(chartimage))
                {

                    var image = iTextSharp.text.Image.GetInstance(imageSys, System.Drawing.Imaging.ImageFormat.Wmf);
                    image.ScalePercent(50f);

                    image.SetAbsolutePosition(document.LeftMargin + 40, document.BottomMargin + 95);

                    document.Add(image);
                }

            }

var image = iTextSharp.text.Image.GetInstance(imageSys, System.Drawing.Imaging.ImageFormat.Wmf);

static void Main(string[] args) {

    // Create a chart.
    Chart chart1 = new Chart();
    chart1.ChartAreas.Add(new ChartArea());
    Series series1 = new Series();
    series1.Points.Add(new DataPoint(1, 2));
    series1.Points.Add(new DataPoint(2, 4));
    series1.Points.Add(new DataPoint(3, 1));
    chart1.Series.Add(series1);

    // Save the chart to an in-memory (emf) metafile.
    Metafile metafile;
    using (MemoryStream str1 = new MemoryStream()) {
        chart1.SaveImage(str1, ChartImageFormat.Emf);

        byte[] emfBytes = str1.ToArray();
        IntPtr hemf = SetEnhMetaFileBits((uint) emfBytes.Length, emfBytes);
        metafile = new Metafile(hemf, true);
    }

    // Convert the metafile to a WMF and write to a file.
    byte[] wmfBytes = GetWmfByteArray(metafile);
    File.WriteAllBytes(@"c:temptest.wmf", wmfBytes);

    // Initialize the document.
    PdfWriter writer = new PdfWriter(@"c:temptest.pdf");
    PdfDocument pdf = new PdfDocument(writer);
    Document document = new Document(pdf);

    // Add the image.
    PdfFormXObject xObject1 = new PdfFormXObject(new WmfImageData(@"c:temptest.wmf"), pdf);
    Image img1 = new Image(xObject1);
    document.Add(img1);

    document.Close();
}

[DllImport("gdiplus.dll", SetLastError = true)]
static extern int GdipEmfToWmfBits(int hEmf, int uBufferSize, byte[] bBuffer, int iMappingMode, EmfToWmfBitsFlags flags);
[DllImport("gdi32.dll")]
public static extern IntPtr SetEnhMetaFileBits(uint cbBuffer, byte[] lpBuffer);

[Flags]
private enum EmfToWmfBitsFlags
{
    EmfToWmfBitsFlagsDefault = 0x00000000,
    EmfToWmfBitsFlagsEmbedEmf = 0x00000001,
    EmfToWmfBitsFlagsIncludePlaceable = 0x00000002,
    EmfToWmfBitsFlagsNoXORClip = 0x00000004
}

private static byte[] GetWmfByteArray(Metafile mf) {
    const int MM_ANISOTROPIC = 8;
    int handle = mf.GetHenhmetafile().ToInt32();
    int bufferSize = GdipEmfToWmfBits(handle, 0, null, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsIncludePlaceable);
    byte[] buf = new byte[bufferSize];
    GdipEmfToWmfBits(handle, bufferSize, buf, MM_ANISOTROPIC, EmfToWmfBitsFlags.EmfToWmfBitsFlagsIncludePlaceable);
    return buf;
}