''' <summary>
''' Adds a new empty page into PDF document.
''' </summary>
''' <param name="pdfFileName">The filename of PDF document.</param>
''' <param name="pageSize">The size of page.</param>
Public Shared Sub AddEmptyPageToPdfDocument(pdfFileName As String, pageSize As System.Drawing.SizeF)
    ' open PDF document
    Using document As New Vintasoft.Imaging.Pdf.PdfDocument(pdfFileName)
        ' get the collection of pages of PDF document
        Dim pages As Vintasoft.Imaging.Pdf.Tree.PdfPageCollection = document.Pages

        ' add an empty page into collection of pages
        pages.Add(pageSize)

        ' save changes to a file
        document.SaveChanges()
    End Using
End Sub

/// <summary>
/// Adds a new empty page into PDF document.
/// </summary>
/// <param name="pdfFileName">The filename of PDF document.</param>
/// <param name="pageSize">The size of page.</param>
public static void AddEmptyPageToPdfDocument(string pdfFileName, System.Drawing.SizeF pageSize)
{
    // open PDF document
    using (Vintasoft.Imaging.Pdf.PdfDocument document = 
        new Vintasoft.Imaging.Pdf.PdfDocument(pdfFileName))
    {
        // get the collection of pages of PDF document
        Vintasoft.Imaging.Pdf.Tree.PdfPageCollection pages = document.Pages;

        // add an empty page into collection of pages
        pages.Add(pageSize);

        // save changes to a file
        document.SaveChanges();
    }
}