Hi George616,

You need to use GridView OnRowDataBound event.

Check this example. Now please take its reference and correct your code.

Database

I have made use of the following table with the schema as follows.

You can download the database table SQL by clicking the download link below.

Download SQL file

For more details you can refer below article.

Display Binary Image from database in ASP.Net GridView control using C# and VB.Net

HTML

<asp:GridView ID="GridView1" runat="server" OnRowDataBound="OnRowDataBound"
    OnRowDeleting="OnRowDeleting" class="table table-bordered table-condensed table-hover" Width="100%">
    <EmptyDataTemplate>
        <div style="text-align: center; font-weight: bolder; font-size: medium;">
            <asp:Label ID="labelTemp" runat="server" Text="No Activity Recorded"></asp:Label>
        </div>
    </EmptyDataTemplate>
    <Columns>
        <asp:TemplateField HeaderText="Image">
            <ItemTemplate>
                <asp:Image ID="Image1" runat="server" Width="30px" Height="30px" />
            </ItemTemplate>
        </asp:TemplateField>
        <asp:CommandField ButtonType="Button" ShowDeleteButton="true" />
    </Columns>
</asp:GridView>

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection conn = new SqlConnection(constr))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter("SELECT Name,ContentType,Data FROM tblFiles", conn))
            {
                DataTable dt = new DataTable();
                sda.Fill(dt);
                GridView1.DataSource = dt;
                GridView1.DataBind();
            }
        }
    }
}

protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DataRowView dr = (DataRowView)e.Row.DataItem;

        if (dr["ContentType"].ToString() != "image/jpeg")
        {
            (e.Row.Cells[1].Controls[0] as Button).Visible = false;
        }

        if (dr.Row.Table.Columns.Contains("Data"))
        {
            if (dr["Data"] != DBNull.Value)
            {
                string imageUrl = "data:image/jpg;base64," + Convert.ToBase64String((byte[])dr["Data"]);
                (e.Row.FindControl("Image1") as Image).ImageUrl = imageUrl;
            }
        }
    }

    GridViewRow row = e.Row;
    List<TableCell> cells = new List<TableCell>();
    foreach (DataControlField column in GridView1.Columns)
    {
        TableCell cell = row.Cells[0];
        row.Cells.Remove(cell);
        cells.Add(cell);
    }
    row.Cells.AddRange(cells.ToArray());
}

protected void OnRowDeleting(object sender, GridViewDeleteEventArgs e)
{

}

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
        Using conn As SqlConnection = New SqlConnection(constr)
            Using sda As SqlDataAdapter = New SqlDataAdapter("SELECT Name,ContentType,Data FROM tblFiles", conn)
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                GridView1.DataSource = dt
                GridView1.DataBind()
            End Using
        End Using
    End If
End Sub

Protected Sub OnRowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim dr As DataRowView = CType(e.Row.DataItem, DataRowView)
        If dr("ContentType").ToString() <> "image/jpeg" Then
            TryCast(e.Row.Cells(1).Controls(0), Button).Visible = False
        End If
        If dr.Row.Table.Columns.Contains("Data") Then
            If Not IsDBNull(dr("Data")) Then
                Dim imageUrl As String = "data:image/jpg;base64," & Convert.ToBase64String(CType(dr("Data"), Byte()))
                TryCast(e.Row.FindControl("Image1"), Image).ImageUrl = imageUrl
            End If
        End If
    End If

    Dim row As GridViewRow = e.Row
    Dim cells As List(Of TableCell) = New List(Of TableCell)()
    For Each column As DataControlField In GridView1.Columns
        Dim cell As TableCell = row.Cells(0)
        row.Cells.Remove(cell)
        cells.Add(cell)
    Next
    row.Cells.AddRange(cells.ToArray())
End Sub

Protected Sub OnRowDeleting(ByVal sender As Object, ByVal e As GridViewDeleteEventArgs)
End Sub

Screenshot