How to insert image in PDF and merge with multiple PDF documents with PDF version 1.7 using C#

using Syncfusion.Pdf;
using Syncfusion.Pdf.Graphics;
using Syncfusion.Pdf.Parsing;
using System.Drawing;

Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics
Imports Syncfusion.Pdf.Parsing
Imports System.Drawing

//Create a new PDF document
PdfDocument document = new PdfDocument();
 
//Set the page size to A4
document.PageSettings.Size = PdfPageSize.A4;
 
//Set margin
document.PageSettings.Margins.All = 0;
 
//Set the PDF version 
document.FileStructure.Version = PdfVersion.Version1_7;
 
//Set the incremental update as false
document.FileStructure.IncrementalUpdate = false;
 
//Add a page to the document
PdfPage page = document.Pages.Add();
 
//Create PDF graphics for the page
PdfGraphics graphics = page.Graphics;
 
//Load the image from the disk
PdfBitmap image = new PdfBitmap("../../Data/Autumn Leaves.jpg");
 
//Draw the image
graphics.DrawImage(image, new RectangleF(0,0,page.GetClientSize().Width, page.GetClientSize().Height));
 
//File path to merge the PDF file
string file1 = "../../Data/Input1.pdf";
string file2 = "../../Data/Input2.pdf";
 
//Create the templates from an existing PDF document page and draw it in on a new PDF document
DrawPDFTemplate(file1, document);
DrawPDFTemplate(file2, document);
 
//Save the document
document.Save("Sample.pdf");
 
//Close the document
document.Close(true);
 
//This will open the PDF file and the result will be seen in the default PDF Viewer
Process.Start("Sample.pdf");

/// <summary>
/// Create the templates from an existing PDF document page and draw it in on a new PDF document
/// </summary>
/// <param name="file"></param>
/// <param name="document"></param>
private void DrawPDFTemplate(string file, PdfDocument document)
{
    //Load a PDF document
    PdfLoadedDocument ldoc = new PdfLoadedDocument(file);
 
    for (int i = 0; i < ldoc.Pages.Count; i++)
    {
        //Get loaded page as a template
        PdfTemplate template = ldoc.Pages[i].CreateTemplate();
 
        //Create a new page
        PdfPage page = document.Pages.Add();
 
        //Create Pdf graphics for the page 
        PdfGraphics g = page.Graphics;
 
        //Draw template with the size as page size
        g.DrawPdfTemplate(template, new PointF(0, 0), new SizeF(page.GetClientSize().Width, page.GetClientSize().Height));
    }
}

'Create a new PDF document 
Dim document As PdfDocument = New PdfDocument()
 
'Set the page size to A4
document.PageSettings.Size = PdfPageSize.A4
 
'Set margin
document.PageSettings.Margins.All = 0
 
'Set the PDF version 
document.FileStructure.Version = PdfVersion.Version1_7
 
'Set the incremental update as false
document.FileStructure.IncrementalUpdate = False
 
'Add a page to the document
Dim page As PdfPage = document.Pages.Add()
 
'Create PDF graphics for the page
Dim graphics As PdfGraphics = page.Graphics
 
'Load the image from the disk
Dim image As PdfBitmap = New PdfBitmap("../../Data/Autumn Leaves.jpg")
 
'Draw the image 
graphics.DrawImage(image, New RectangleF(0, 0, page.GetClientSize().Width, page.GetClientSize().Height))
 
'File path to merge the PDF file 
Dim file1 As String = "../../Data/Input1.pdf"
Dim file2 As String = "../../Data/Input2.pdf"
 
'Create the templates from an existing PDF document page and draw it in on a new PDF document 
DrawPDFTemplate(file1, document)
DrawPDFTemplate(file2, document)
 
'Save the document
document.Save("Sample.pdf")
 
'Close the document
document.Close(True)
 
'This will open the PDF file and the result will be seen in the default PDF Viewer
Process.Start("Sample.pdf")

''' <summary>
''' Create the templates from an existing PDF document page and draw it in on a new PDF document
''' </summary>
''' <param name="file"></param>
''' <param name="document"></param>
Private Sub DrawPDFTemplate(ByVal file As String, ByVal document As PdfDocument)
 
    'Load a PDF document
    Dim ldoc As PdfLoadedDocument = New PdfLoadedDocument(file)
 
    For i As Integer = 0 To ldoc.Pages.Count - 1
 
        'Get loaded page as a template 
        Dim template As PdfTemplate = ldoc.Pages(i).CreateTemplate()
 
        'Create a new page 
        Dim page As PdfPage = document.Pages.Add()
 
        'Create Pdf graphics for the page  
        Dim g As PdfGraphics = page.Graphics
 
        'Draw template with the size as page size 
        g.DrawPdfTemplate(template, New PointF(0, 0), New SizeF(page.GetClientSize().Width, page.GetClientSize().Height))
 
    Next
End Sub