A simple to use Photo Gallery, tell it where to look and it creates a set of images, the layout of which can be controlled with CSS.
It takes one entry in web.config to wire up the thumbnail generator like this
Source of /samples/gallery.aspx
<%@ Page Title="Gallery Control Demonstration" Language="vb" AutoEventWireup="false" MasterPageFile="~/samples/sample.master" CodeBehind="gallery.aspx.vb" Inherits="www.aviationwebdesign.co.uk.gallery" %>

<%@ Register Assembly="AWDServerControls" Namespace="AWDServerControls" TagPrefix="awdControls" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<h1>Gallery Control Demo</h1>
    <awdControls:gallery ID="Gallery1" runat="server" folder="/samples/images/" />
</asp:Content>