How to update an image in a gridview using upload button for each row?

<asp:GridView ID="gridAdayPreprcircltimactiv" runat="server" AutoGenerateColumns="False" 
            onselectedindexchanged="gridAdayPreprcircltimactiv_SelectedIndexChanged">
            <columns>
                <asp:BoundField DataField="intAdayPreprcircltimactivId" HeaderText="AdayPreprcircltimactivId" 
                    InsertVisible="False" ReadOnly="True" SortExpression="ID" />
                <asp:BoundField DataField="strAdayPreprcircltimactivText" HeaderText="AdayPreprcircltimactivText" 
                    InsertVisible="False" ReadOnly="True" SortExpression="ID" />
                <asp:TemplateField HeaderText="Image">
                    <itemtemplate>
                        <asp:Image ID="Image1" runat="server" Height="28px" 
                            ImageUrl='<%# "HandlerAdayPreprcircltimactiv.ashx?intAdayPreprcircltimactivId=" + Eval("intAdayPreprcircltimactivId")%>' Width="23px" />
                    </itemtemplate>
                
                <asp:CommandField HeaderText="Select" ShowSelectButton="True" />
            </columns>

protected void btnsave_Click(object sender, EventArgs e)
    {
        FileUpload img = (FileUpload)upload_file;
        Byte[] imgByte = null;
        if (upload_file.HasFile && img.PostedFile != null)
        {
            HttpPostedFile File = upload_file.PostedFile;
            imgByte = new Byte[File.ContentLength];
            File.InputStream.Read(imgByte, 0, File.ContentLength);
        }

        string sql = "INSERT INTO DPSAdayPreprcircltimactiv(intAdayPreprcircltimactivId,strAdayPreprcircltimactivText,strImageurl) VALUES(@intAdayPreprcircltimactivId,@strAdayPreprcircltimactivText,@strImageurl)";
        SqlCommand cmd = new SqlCommand(sql, (SqlConnection)Application.Get("DPS"));
        cmd.Parameters.AddWithValue("@intAdayPreprcircltimactivId", txtAdayPreprcircltimactivid.Text.Trim());
        cmd.Parameters.AddWithValue("@strAdayPreprcircltimactivText", txtAdayPreprcircltimactiv.Text.Trim());
        cmd.Parameters.AddWithValue("@strImageurl", imgByte);
        cmd.ExecuteNonQuery();
        load_dgitems();
   
    }

protected void btnupdate_Click(object sender, EventArgs e)
    {
        FileUpload img = (FileUpload)upload_file;
        Byte[] imgByte = null;
        if (upload_file.HasFile && img.PostedFile != null)
        {
            HttpPostedFile File = upload_file.PostedFile;
            imgByte = new Byte[File.ContentLength];
            File.InputStream.Read(imgByte, 0, File.ContentLength);
        }
        string sql = "update DPSAdayPreprcircltimactiv set strAdayPreprcircltimactivText=@strAdayPreprcircltimactivText,strImageurl=@strImageurl where intAdayPreprcircltimactivId=@intAdayPreprcircltimactivId";
        SqlCommand cmd = new SqlCommand(sql, (SqlConnection)Application.Get("DPS"));
        cmd.Parameters.AddWithValue("@strAdayPreprcircltimactivText", txtAdayPreprcircltimactiv.Text.Trim());
        cmd.Parameters.AddWithValue("@strImageurl", imgByte);
        cmd.Parameters.AddWithValue("@intAdayPreprcircltimactivId", txtAdayPreprcircltimactivid.Text.Trim());
        cmd.ExecuteNonQuery();
        load_dgitems();
    }

<%@ WebHandler Language="C#" Class="HandlerAdayPreprcircltimactiv" %>

using System;
using System.Web;
using System.Configuration;
using System.Data.SqlClient;

public class HandlerAdayPreprcircltimactiv : IHttpHandler {
    
    public void ProcessRequest (HttpContext context) 
    {
        SqlConnection con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings["conn"].ConnectionString;

        // Create SQL Command 

        SqlCommand cmd = new SqlCommand();
        cmd.CommandText = "Select intAdayPreprcircltimactivId,strAdayPreprcircltimactivText,strImageurl from DPSAdayPreprcircltimactiv where intAdayPreprcircltimactivId =@intAdayPreprcircltimactivId";
        cmd.CommandType = System.Data.CommandType.Text;
        cmd.Connection = con;

        SqlParameter ImageID = new SqlParameter("@intAdayPreprcircltimactivId", System.Data.SqlDbType.Int);
        ImageID.Value = context.Request.QueryString["intAdayPreprcircltimactivId"];
        cmd.Parameters.Add(ImageID);
        con.Open();
        SqlDataReader dReader = cmd.ExecuteReader();
        dReader.Read();
        context.Response.BinaryWrite((byte[])dReader["strImageurl"]);
        dReader.Close();
        con.Close();
        //context.Response.ContentType = "text/plain";
        //context.Response.Write("Hello World");
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }

}