In ASP.NET AJAX Control toolkit there is an extender known as SlideShowExtender. This can be used to create a Slide show by looping through the images. The images are shown in the SlideShow by using a PageMethod or a Webservice.

Example:

<div>
        /*Add a script manager in your page */
        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
 
       /*This is the initial image that will be shown to the user*/
       <div>
             <asp:Image ID="img1" runat="server"
                                    Height="400px" 
                                   Width="400px"
                                   ImageUrl="~/images/aa.jpg" />
       </div>    
 
       /*Drag and Drop a SlideShowExtender*/   
       <cc1:SlideShowExtender ID="SlideShowExtender1" runat="server"
                                                     BehaviorID="SlideShowBehaviorID"
                                                     TargetControlID="img1"
                                                     SlideShowServiceMethod="GetImagesForSlide"
   AutoPlay="true"
 ImageDescriptionLabelID="lblDesc"
                                                     NextButtonID="btnNext"
                                                     PreviousButtonID="btnPrev"
                                                     PlayButtonID="btnPlay"
  PlayButtonText="Play"
      StopButtonText="Stop"
                   Loop="true" >
       </cc1:SlideShowExtender>        
       <div>
            /*Description about the image will be shown in this Label*/
     <asp:Label ID="lblDesc" runat="server" Text=""></asp:Label><br />
 
           /*Previous, Next Button to see the previous, next image and Play and  stop button to start and stop the  slide show */
         <asp:Button ID="btnPrev" runat="server" Text="Previous" />
         <asp:Button ID="btnPlay" runat="server" Text="" />
         <asp:Button ID="btnNext" runat="server" Text="Next" />
        </div>
 </div>

The SlideShowExtender uses a page method(GetImagesForSlide).In code behind add the following page method.

[System.Web.Services.WebMethod]
  [System.Web.Script.Services.ScriptMethod]
    public static AjaxControlToolkit.Slide[] GetImagesForSlide()
     {
         AjaxControlToolkit.Slide[] imgSlide = new AjaxControlToolkit.Slide[4];
 

         /*Provide some images for slide show*/

         imgSlide[0] = new AjaxControlToolkit.Slide("images/aa.jpg",    "Flower", "Flower");
         imgSlide[1] = new   AjaxControlToolkit.Slide("images/atlanta.jpg","City", "Atlanta");
         imgSlide[2] = new AjaxControlToolkit.Slide("images/img1.jpg","Picture", "Imagine");
         imgSlide[3] = new AjaxControlToolkit.Slide("images/logo.png", "Team Logo", "Logo");
         return (imgSlide);
     }