<asp:TemplateField>
    <ItemTemplate>
        <asp:ImageButton ID="imgbtnEdit" CommandName="Edit" runat="server" />
    </ItemTemplate>
</asp:TemplateField>

protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
            int screenshotId = Convert.ToInt32(DataBinder.Eval(e.Row.DataItem, "screenshotId"));
            ImageButton btnShowImage = e.Row.FindControl("imgbtnEdit") as ImageButton;

            if (screenshotId > 0)
            {
                btnShowImage.Visible = true;
                Response.Write(screenshotId + "<br />"); //here the value are 1
            }
            else
            {
                btnShowImage.Visible = false;
            }

    }

}