This sample shows how to make thumbnail of a PDF page.

Use PdfDrawOptions.CreateFitSize method to setup drawing options. This will cause page to be drawn as an image of the specified size. Then pass created PdfDrawOptions to PdfPage.Save method to save thumbnail of the page to a stream or a file.

There are also PdfDrawOptions.CreateFitWidth and PdfDrawOptions.CreateFitHeight methods. These methods are useful when you need thumbnail images of specified width or height and have no requirements for the second dimension of thumbnail images.

Making of thumbnail of a PDF page is not supported in version for .NET Standard.

C#
using System.Diagnostics;

using BitMiracle.Docotic.Pdf;

namespace BitMiracle.Docotic.Pdf.Samples
{
    public static class MakePageThumbnail
    {
        public static void Main()
        {
            // NOTE: 
            // When used in trial mode, the library imposes some restrictions.
            // Please visit http://bitmiracle.com/pdf-library/trial-restrictions.aspx
            // for more information.

            string pathToImage = "MakePageThumbnail.png";

            using (PdfDocument pdf = new PdfDocument(@"Sample Data/jfif3.pdf"))
            {
                PdfDrawOptions options = PdfDrawOptions.CreateFitSize(new PdfSize(200, 200), false);
                options.BackgroundColor = new PdfGrayColor(100);
                pdf.Pages[0].Save(pathToImage, options);
            }

            Process.Start(pathToImage);
        }
    }
}
VB
Imports System.Diagnostics

Imports BitMiracle.Docotic.Pdf

Namespace BitMiracle.Docotic.Pdf.Samples
    Public NotInheritable Class MakePageThumbnail
        Public Shared Sub Main()
            ' NOTE: 
            ' When used in trial mode, the library imposes some restrictions.
            ' Please visit http://bitmiracle.com/pdf-library/trial-restrictions.aspx
            ' for more information.

            Dim pathToImage As String = "MakePageThumbnail.png"

            Using pdf As New PdfDocument("Sample Data/jfif3.pdf")
                Dim options As PdfDrawOptions = PdfDrawOptions.CreateFitSize(New PdfSize(200, 200), False)
                options.BackgroundColor = New PdfGrayColor(100)
                pdf.Pages(0).Save(pathToImage, options)
            End Using

            Process.Start(pathToImage)
        End Sub
    End Class
End Namespace