How to convert PDF to PNG

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

Imports Syncfusion.Pdf.Parsing
Imports System.Drawing
Imports System.Drawing.Imaging

//Loaded input PDF file
PdfLoadedDocument loadedDocument = new PdfLoadedDocument("MultiColumnReports.pdf");
//Exporting specify page index as image
Bitmap image = loadedDocument.ExportAsImage(0);
//Save the image as PNG format
image.Save("Image.png", ImageFormat.Png);
//Close the document
loadedDocument.Close(true);

'Loaded input PDF file
Dim loadedDocument As New PdfLoadedDocument("MultiColumnReports.pdf")
'Exporting specify page index as image
Dim image As Bitmap = loadedDocument.ExportAsImage(0)
'Save the image as PNG format
image.Save("Image.png", ImageFormat.Png)
'Close the document
loadedDocument.Close(True)