public void InsertImageToPage()
{
    //Initialize library
    PdfCommon.Initialize();

    //Load document
    pdfViewer1.LoadDocument(@"c:\test002.pdf");
    var doc = pdfViewer1.Document;

    //Create .Net bitmap from file and lock bits for copy into pdf image
    Bitmap bmp = (Bitmap)Bitmap.FromFile(@"c:\sample_image.jpg");
    var bi = bmp.LockBits(
        new Rectangle(0, 0, bmp.Width, bmp.Height),
        ImageLockMode.ReadOnly,
        PixelFormat.Format32bppArgb);

    //Create PdfBitmap object from .Net bitmap
    var bitmap = new PdfBitmap(
        bmp.Width,
        bmp.Height,
        BitmapFormats.FXDIB_Argb,
        bi.Scan0,
        bi.Stride);

    //Create pdf image object and then set PdfBitmap object into it.
    var image = PdfImageObject.Create(doc);
    image.SetBitmap(bitmap);

    //Move image object to 0,0 and set it's size to 1px;
    image.SetMatrix(1, 0, 0, 1, 0, 0);
    //Scale image object to it's actual width and heihgt
    image.Transform(bmp.Width, 0, 0, bmp.Height, 0, 0);

    //Insert blank page into document
    //Get the newly added page and insert image object into page
    doc.Pages.InsertPageAt(doc.Pages.Count, 900, 900);
    var page = doc.Pages[doc.Pages.Count - 1];
    page.PageObjects.InsertObject(image);

    //Save PDF document to the file
    page.GenerateContent();
    doc.Save(@"c:\test002_modified.pdf", Patagames.Pdf.Enums.SaveFlags.NoIncremental);
}

pdfViewer1.ClearRenderBuffer();
pdfViewer1.Invalidate();