<asp:DataList ID="DataList1" runat="server">

                <ItemTemplate>

                    <asp:Label ID="lbNwes" runat="server" Text='<%#Eval("Id")%>'></asp:Label>

                    &nbsp;

            <a href="<%# "ImageHandler.ashx?ImID="+ Eval("mainid") %>" target="_blank" title="点击放大看">

                <asp:Image ID="Image1" Width="100px" Height="100px" runat="server" ImageUrl='<%# "ImageHandler.ashx?ImID="+ Eval("mainid") %>' />

            </a>

                    <asp:Image ID="Image2" runat="server" Width="100px" Height="100px" />

                </ItemTemplate>

            </asp:DataList>

 public void ProcessRequest(HttpContext context)

        {

            context.Response.ContentType = "image/gif";

            string imageid = context.Request.QueryString["ImID"];

            byte[] MyData = new byte[];

            using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["strconn"].ConnectionString))

            {

                conn.Open();

                SqlCommand cmd = new SqlCommand();

                cmd.Connection = conn;

                cmd.CommandText = "select Data from Blobs where mainid=" + imageid;

                SqlDataReader sdr = cmd.ExecuteReader();

                sdr.Read();

                MyData = (byte[])sdr["Data"];

                context.Response.BinaryWrite(MyData);

            }

        }