How to Convert PDF to GIF in ASP.NET?

using System;
using System.Web.UI;
using System.IO;
using PQScan.PDFToImage;

public partial class _Default: System.Web.UI.Page
{
  protected void Page_Load(object sender, EventArgs e)
  {
    // Get your PDF document ready.
    string pdfFileName = Server.MapPath("sample.pdf");

    // Create an instance of PQScan.PDFToImage.PDFDocument object.
    PDFDocument pdfDoc = new PDFDocument();

    // Load your PDF document.
    pdfDoc.LoadPDF(pdfFileName);

    // Prepare response.
    Response.Clear();
    Response.ContentType = "image/gif";

    // Turn the first page of your PDF document to the output image.
    System.Drawing.Image gifImage = pdfDoc.ToImage(0);

    using (MemoryStream ms = new MemoryStream())
    {
      // Save image as gif format.
      gifImage.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);

      // Show gif image to the aspx web page.
      Response.OutputStream.Write(ms.GetBuffer(), 0, (int)ms.Length);
    }

    gifImage.Dispose();

    Response.End();
  }
}

Imports System
Imports System.Web.UI
Imports System.IO
Imports PQScan.PDFToImage

Public partial Class _Default
     Inherits System.Web.UI.Page
  Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
    ' Prepare a sample PDF file.
    Dim pdfFileName As String = Server.MapPath("sample.pdf")

    ' Create an instance of PQScan.PDFToImage.PDFDocument object.
    Dim pdfDoc As PDFDocument = New PDFDocument()

    ' Load the PDF file.
    pdfDoc.LoadPDF(pdfFileName)

    ' Prepare response.
    Response.Clear()
    Response.ContentType = "image/gif"

    ' Transform the first page of PDF file to the output image.
    Dim gifImage As System.Drawing.Image = pdfDoc.ToImage(0)

    Imports (MemoryStream ms = New MemoryStream())
    {
      ' Save image as gif format.
      gifImage.Save(ms, System.Drawing.Imaging.ImageFormat.Gif)

      ' Display gif image to the aspx web page.
      Response.OutputStream.Write(ms.GetBuffer(), 0, CType(ms.Length, Integer))
    }

    gifImage.Dispose()

    Response.End()
  End Sub
End Class