Hi IamAzhar,

Refer below sample.

I have taken below article help to create this sample.

Dynamically generate and display Thumbnail picture by resizing the Image in ASP.Net

HTML

<asp:Image runat="server" ID="img1"  />

Namespaces

C#

using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.IO;
using System.Drawing.Imaging;

VB.Net

Imports System.Data.SqlClient
Imports System.Configuration
Imports System.Data
Imports System.IO
Imports System.Drawing.Imaging

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        SqlConnection con = new SqlConnection(constr);
        SqlCommand cmd = new SqlCommand("SELECT TOP 2 Name, Data FROM tblfiles", con);
        SqlDataAdapter da = new SqlDataAdapter(cmd);
        DataTable dt = new DataTable();
        da.Fill(dt);
        string name = dt.Rows[0]["Name"].ToString();
        byte[] byteee = (byte[])dt.Rows[0]["Data"];
        string filePath = "~/File/" + name;
        File.WriteAllBytes(Server.MapPath(filePath), byteee);
        string path = Server.MapPath(filePath);

        System.Drawing.Image image = System.Drawing.Image.FromFile(path);
        using (System.Drawing.Image thumbnail = image.GetThumbnailImage(100, 100, new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero))
        {
            using (MemoryStream memoryStream = new MemoryStream())
            {
                thumbnail.Save(memoryStream, ImageFormat.Jpeg);
                Byte[] bytes = new Byte[memoryStream.Length];
                memoryStream.Position = 0;
                memoryStream.Read(bytes, 0, (int)bytes.Length);
                string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
                img1.ImageUrl = "data:image/png;base64," + base64String;
            }
        }
    }
}

public bool ThumbnailCallback()
{
    return false;
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
        Dim con As SqlConnection = New SqlConnection(constr)
        Dim cmd As SqlCommand = New SqlCommand("SELECT TOP 2 Name, Data FROM tblfiles", con)
        Dim da As SqlDataAdapter = New SqlDataAdapter(cmd)
        Dim dt As DataTable = New DataTable()
        da.Fill(dt)
        Dim name As String = dt.Rows(0)("Name").ToString()
        Dim byteee As Byte() = CType(dt.Rows(0)("Data"), Byte())
        Dim filePath As String = "~/File/" & name
        File.WriteAllBytes(Server.MapPath(filePath), byteee)
        Dim path As String = Server.MapPath(filePath)
        Dim image As System.Drawing.Image = System.Drawing.Image.FromFile(path)
        Using thumbnail As System.Drawing.Image = image.GetThumbnailImage(100, 100, New System.Drawing.Image.GetThumbnailImageAbort(AddressOf ThumbnailCallback), IntPtr.Zero)
            Using memoryStream As MemoryStream = New MemoryStream()
                thumbnail.Save(memoryStream, ImageFormat.Jpeg)
                Dim bytes As Byte() = New Byte(memoryStream.Length - 1) {}
                memoryStream.Position = 0
                memoryStream.Read(bytes, 0, CInt(bytes.Length))
                Dim base64String As String = Convert.ToBase64String(bytes, 0, bytes.Length)
                img1.ImageUrl = "data:image/png;base64," & base64String
            End Using
        End Using
    End If
End Sub

Public Function ThumbnailCallback() As Boolean
    Return False
End Function

Screenshot