Display/Store and Retrieve Image Data from Database to Gridview, and also on Mouse Over

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Configuration;
//using Algem.WebControls;
using System.Data.SqlClient;
using System.Text;
using System.Data;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using Utils;

public partial class ThumbExpand : System.Web.UI.Page
{
    string sqlConnection = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
    SqlConnection conn;
    SqlCommand cmd;

    protected void Page_Load(object sender, EventArgs e)
    {
        BindGrid();
    }

    protected void BindGrid()
    {
        List<User> lst = new List<User>();
        try
        {
            using (conn = new SqlConnection(sqlConnection))
            {
                conn.Open();

                StringBuilder sbQry = new StringBuilder();
                sbQry.Append("SELECT UserId, UserName,Password,LastName,");
                sbQry.Append("FirstName,MiddleName,WorksiteCode,AccessLevel,");
                sbQry.Append("Active,DateCreated,DateUpdated,Worksitedesc,Picture FROM dbo.[User]");
                using (cmd = new SqlCommand(sbQry.ToString(), conn))
                {
                    cmd.CommandType = CommandType.Text;

                    using (SqlDataReader dr = cmd.ExecuteReader())
                    {
                        while (dr.Read())
                        {
                            User temp = new User();
                            temp.UserID = Tools.Tools.IifInt(dr["userID"]);
                            temp.Username = Tools.Tools.IifStr(dr["Username"]);
                            temp.Password = Tools.Tools.IifStr(dr["Password"]);
                            temp.LastName = Tools.Tools.IifStr(dr["LastName"]);
                            temp.FirstName = Tools.Tools.IifStr(dr["FirstName"]);
                            temp.MiddleName = Tools.Tools.IifStr(dr["MiddleName"]);
                            temp.WorksiteCode = Tools.Tools.IifStr(dr["WorksiteCode"]);
                            temp.AccessLevel = Tools.Tools.IifInt(dr["AccessLevel"]);
                            temp.Active = Tools.Tools.IifStr(dr["Active"]);
                            temp.DateCreated = Tools.Tools.IifDT(dr["DateCreated"]);
                            temp.DateUpdated = Tools.Tools.IifDT(dr["DateUpdated"]);
                            temp.WorksiteCode = Tools.Tools.IifStr(dr["Worksitedesc"]);
                            temp.Picture = ResizeImage(dr["Picture"], 500);
                            lst.Add(temp);
                        }
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }        if (lst.Count > 0)
        {
            this.lblNoRecord.Visible = false;
        }
        else
        {
            this.lblNoRecord.Visible = true;
        }
        this.DataList1.DataSource = lst;
        this.DataList1.DataBind();
    }

    private System.Drawing.Image ResizeImage(object p, int targetSize)
    {
        using (System.Drawing.Image oldImage = System.Drawing.Image.FromStream(new MemoryStream((byte[])p)))
        {
            Size newSize = CalculateDimensions(oldImage.Size, targetSize);
            using (Bitmap newImage = new Bitmap(newSize.Width, newSize.Height, PixelFormat.Format24bppRgb))
            {
                using (Graphics canvas = Graphics.FromImage(newImage))
                {
                    canvas.SmoothingMode = SmoothingMode.AntiAlias;
                    canvas.InterpolationMode = InterpolationMode.HighQualityBicubic;
                    canvas.PixelOffsetMode = PixelOffsetMode.HighQuality;
                    canvas.DrawImage(oldImage, new Rectangle(new Point(0, 0), newSize));
                    MemoryStream m = new MemoryStream();
                    newImage.Save(m, ImageFormat.Jpeg);

                    var imageFile = m;
                    var xx = System.Drawing.Image.FromStream(new MemoryStream(m.GetBuffer()));
                    System.Drawing.Image theImage = xx;
                    return theImage;

                }
            }
        }
    }


    private static Size CalculateDimensions(Size oldSize, int targetSize)
    {
        Size newSize = new Size();
        if (oldSize.Height > oldSize.Width)
        {
            newSize.Width = (int)(oldSize.Width * ((float)targetSize / (float)oldSize.Height));
            newSize.Height = targetSize;
        }
        else
        {
            newSize.Width = targetSize;
            newSize.Height = (int)(oldSize.Height * ((float)targetSize / (float)oldSize.Width));
        }
        return newSize;
    }


    protected void btnBack_Click(object sender, EventArgs e)
    {

        SessionManager.PageIndex = this.hfKeyId.Value;
        SessionManager.PageIndex = this.hfPageIndex.Value;
        Response.Redirect("~/Welcome.aspx");
    }
}