Convert Powerpoint file into Image file

Hi guys, we can convert all slides of the PowerPoint file into seperate image format, we need to include Microsoft.Office.Interop.PowerPoint as name space

using Microsoft.Office.Interop.PowerPoint;
using Microsoft.Office.Core;
using System.IO;

try
  {
      FileInfo objfile = new FileInfo(FileUpload1.PostedFile.FileName);
     if (objfile.Extension.Equals(".ppt"))
       {
          ApplicationClass pptApplication = new Microsoft.Office.Interop.PowerPoint.ApplicationClass();
          Presentation pptPresentation = pptApplication.Presentations.Open(objfile.FullName, MsoTriState.msoFalse, MsoTriState.msoFalse, MsoTriState.msoFalse);
          pptPresentation.Export(objfile.FullName, "jpg", Int32.Parse(pptPresentation.SlideMaster.Width.ToString()), Int32.Parse(pptPresentation.SlideMaster.Height.ToString()));
        }
     else
       {
          Response.Write("Please choose PowerPoint files only");
        }
  }
catch (Exception ex)
   { }