How to draw online images in PDF tables using C# and VB.NET?

using Syncfusion.Pdf;
using Syncfusion.Pdf.Grid;
using Syncfusion.Pdf.Graphics;
using System.Drawing;
using System.Net;
using System.IO;

Imports System.Drawing
Imports System.IO
Imports System.Net
Imports Syncfusion.Pdf
Imports Syncfusion.Pdf.Graphics
Imports Syncfusion.Pdf.Grid

//Create a PDF document
PdfDocument doc = new PdfDocument();
//Add a page
PdfPage page = doc.Pages.Add();
//Create a PdfGrid
PdfGrid pdfGrid = new PdfGrid();
//Apply built-in table style
pdfGrid.ApplyBuiltinStyle(PdfGridBuiltinStyle.GridTable4);
DataTable dataTable = new DataTable();
dataTable.Columns.Add("Student");
dataTable.Columns.Add("Picked Up By");
dataTable.Columns.Add("Signed");
dataTable.Rows.Add(new object[] { "Aiden Leung", "Sharon Chen:Sharon Chen", "http://www.syncfusion.com/downloads/support/directtrac/general/Signature-2080342779" });
dataTable.Rows.Add(new object[] { "Daniel Hackett", "Timothy Hackett", "http://www.syncfusion.com/downloads/support/directtrac/general/Signature-2080342779" });
//Assign data source
pdfGrid.DataSource = dataTable;
pdfGrid.BeginCellLayout += new PdfGridBeginCellLayoutEventHandler(table_BeginCellLayout);
//Draw grid to the page of PDF document
pdfGrid.Draw(page, new PointF(10, 10));
//Save and close the document
doc.Save("output.pdf");
doc.Close(true);

'Create a PDF document
Dim doc As PdfDocument = New PdfDocument()
'Add a page
Dim page As PdfPage = doc.Pages.Add()
'Create a PdfGrid
Dim pdfGrid As PdfGrid = New PdfGrid()
'Apply built-in table style
pdfGrid.ApplyBuiltinStyle(PdfGridBuiltinStyle.GridTable4)
Dim dataTable As DataTable = New DataTable()
dataTable.Columns.Add("Student")
dataTable.Columns.Add("Picked Up By")
dataTable.Columns.Add("Signed")
dataTable.Rows.Add(New Object() {"Aiden Leung", "Sharon Chen:Sharon Chen", "http://www.syncfusion.com/downloads/support/directtrac/general/Signature-2080342779"})
dataTable.Rows.Add(New Object() {" Daniel Hackett", "Timothy Hackett", "http://www.syncfusion.com/downloads/support/directtrac/general/Signature-2080342779"})
'Assign data source
pdfGrid.DataSource = dataTable
AddHandler pdfGrid.BeginCellLayout, New PdfGridBeginCellLayoutEventHandler(AddressOf table_BeginCellLayout)
'Draw grid to the page of PDF document
pdfGrid.Draw(page, New PointF(10, 10))
'Save and close the document
doc.Save("output.pdf")
doc.Close(True)

//Event to read stream from online image
public void table_BeginCellLayout(object sender, PdfGridBeginCellLayoutEventArgs args)
        {
            if (args.RowIndex != -1 && args.CellIndex == 2)
            {
                //Check the cell value start with https
                if (args.Value.StartsWith("https:\") || args.Value.StartsWith("http:\"))
                {
                    WebClient wc = new WebClient();
                    byte[] bytes = wc.DownloadData(args.Value);
                    MemoryStream ms = new MemoryStream(bytes);
                    PdfBitmap pBmp = new PdfBitmap(ms);
                    PdfGrid grid = sender as PdfGrid;
                    //Set the cell value as empty string
                    grid.Rows[args.RowIndex].Cells[args.CellIndex].Value = "";
                    //Set the image as a background image
                    args.Style.BackgroundImage = pBmp;
                }
            }
        }

'Event to read stream from online image
Public Sub table_BeginCellLayout(ByVal sender As Object, ByVal args As PdfGridBeginCellLayoutEventArgs)
    If ((args.RowIndex <> -1) _
                AndAlso (args.CellIndex = 2)) Then
        'Check the cell value start with https
        If args.Value.StartsWith("https:\") Or args.Value.StartsWith("http:\") Then
            Dim wc As WebClient = New WebClient()
            Dim bytes() As Byte = wc.DownloadData(args.Value)
            Dim ms As MemoryStream = New MemoryStream(bytes)
            Dim pBmp As PdfBitmap = New PdfBitmap(ms)
            Dim grid As PdfGrid = CType(sender, PdfGrid)
            'Set the cell value as empty string
            grid.Rows(args.RowIndex).Cells(args.CellIndex).Value = ""
            'Set the image as a background image
            args.Style.BackgroundImage = pBmp
        End If
    End If
End Sub