My AjaxComplete not showing image, its only showing the usernames and names

cSharp

 [System.Web.Script.Services.ScriptMethod()]
    [System.Web.Services.WebMethod]
    public static List<string> SearchEmployees(string prefixText, int count)
    {
        using (SqlConnection conn = new SqlConnection())
        {
            conn.ConnectionString = ConfigurationManager
                    .ConnectionStrings["conn"].ConnectionString;
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = "select UserName,UserId,Name from User3 where " + "UserName like @SearchText + '%'";
                cmd.Parameters.AddWithValue("@SearchText", prefixText);
                cmd.Connection = conn;
                conn.Open();
                List<string> Searchusernames = new List<string>();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {

                        Searchusernames.Add(AjaxControlToolkit.AutoCompleteExtender
                       .CreateAutoCompleteItem(string.Format("{0} {1}", sdr["Name"], sdr["UserName"]), sdr["UserId"].ToString()));
                    }
                }
                conn.Close();
                return Searchusernames;
            }
        }
    }

html

<div class="input-group">
    <asp:ScriptManager ID="ScriptManager1" runat="server" EnablePageMethods = "true">
    </asp:ScriptManager>
    <asp:TextBox ID="txtContactsSearch" runat="server" class="form-control" placeholder="Search post..." Width="100%"></asp:TextBox>
    <asp:AutoCompleteExtender ServiceMethod="SearchEmployees"
    MinimumPrefixLength="1" CompletionInterval="100" EnableCaching="false" CompletionSetCount="10"
    TargetControlID="txtContactsSearch" OnClientPopulated ="usernames_Populated"
    OnClientItemSelected = "OnEmployeeSelected" ID="AutoCompleteExtender1" runat="server" FirstRowSelected = "false"></asp:AutoCompleteExtender>
    <span class="input-group-btn">
        <asp:LinkButton ID="LinkButton2" runat="server" class="btn btn-default" > 
            <i class="fa fa-search"></i>
        </asp:LinkButton>
    </span>
</div>