Protected Sub convertToPdfButton_Click(ByVal sender As Object, ByVal e As EventArgs)
    ' Create a HTML to PDF converter object with default settings
    Dim htmlToPdfConverter As New HtmlToPdfConverter()

    ' Set license key received after purchase to use the converter in licensed mode
    ' Leave it not set to use the converter in demo mode
    htmlToPdfConverter.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og="

    ' Select all images from HTML page
    htmlToPdfConverter.HtmlElementsMappingOptions.HtmlElementSelectors = New String() {"img"}

    ' Exclude the original images from rendering becuase they will be replaced by an image from local file system
    htmlToPdfConverter.HiddenHtmlElementsSelectors = New String() {"img"}

    Dim pdfDocument As Document = Nothing
    Try
        ' Convert a HTML string with images to replace to a PDF document object
        pdfDocument = htmlToPdfConverter.ConvertUrlToPdfDocumentObject(urlTextBox.Text)

        ' Replace the images selected in HTML using special attributes with images from local file system
        For Each imageElementInfo As HtmlElementMapping In htmlToPdfConverter.HtmlElementsMappingOptions.HtmlElementsMappingResult
            Dim imagePdfPage As PdfPage = imageElementInfo.PdfRectangles(0).PdfPage
            Dim imageRectangle As RectangleF = imageElementInfo.PdfRectangles(0).Rectangle

            Dim newImageElement As New ImageElement(imageRectangle.X, imageRectangle.Y, imageRectangle.Width, imageRectangle.Height, Server.MapPath("~/DemoAppFiles/Input/Images/box.jpg"))
            newImageElement.EnlargeEnabled = True
            imagePdfPage.AddElement(newImageElement)
        Next imageElementInfo

        ' Save the PDF document in a memory buffer
        Dim outPdfBuffer() As Byte = pdfDocument.Save()

        ' Send the PDF as response to browser

        ' Set response content type
        Response.AddHeader("Content-Type", "application/pdf")

        ' Instruct the browser to open the PDF file as an attachment or inline
        Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Replace_with_Higher_Quality_Images.pdf; size={0}", outPdfBuffer.Length.ToString()))

        ' Write the PDF document buffer to HTTP response
        Response.BinaryWrite(outPdfBuffer)

        ' End the HTTP response and stop the current page processing
        Response.End()
    Finally
        ' Close the PDF document
        If pdfDocument IsNot Nothing Then
            pdfDocument.Close()
        End If
    End Try
End Sub