captcha addon anyone?

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using System;
using System.ComponentModel;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;

namespace KeithRull.CS.WebControls
{
    [DefaultProperty("Text")]
    [ToolboxData("<{0}:RandomImageControl runat=server></{0}:RandomImageControl>")]
    public class RandomImageControl : WebControl
    {
        [Bindable(true)]
        [Category("Appearance")]
        [DefaultValue("")]
        [Localizable(true)]
        public string FolderPath
        {
            get
            {
                String s = (String)ViewState["FolderPath"];
                return ((s == null) ? String.Empty : s);
            }

            set
            {
                ViewState["FolderPath"] = value;
            }
        }

        protected override void CreateChildControls()
        {
            Image imagePlaceholder = new Image();

            //create a new session variable if the variable does not exist
            if (ViewState["RandomImageIndex"] == null)
                ViewState["RandomImageIndex"] = 0;

            //the path of our image folder
            string folderPath = FolderPath;
            //read the directory information
            DirectoryInfo directoryInfo = new DirectoryInfo(folderPath);
            //get a list of files contained in our image directory
            FileInfo[] fileInfos = directoryInfo.GetFiles("*.jpg");
            //get the number of files read in the directory
            int fileCount = fileInfos.Length;

            //check whether there is a file or not
            if (fileCount != 0)
            {
                //our random number generator
                Random randomGenerator = new Random((fileCount * DateTime.Now.Second) + DateTime.Now.Millisecond);
                //get the random number
                int randomImageIndex = randomGenerator.Next(fileCount);
                //get the stored value in our session variable
                int storedImageIndex = int.Parse(ViewState["RandomImageIndex"].ToString());
                //compare the current and stored values to see if they are the same

                while (storedImageIndex == randomImageIndex)
                {
                    //generate a new random number if the stored value is the same as the current one.
                    randomImageIndex = randomGenerator.Next(fileCount);
                }
                //the full path of the image
                string fullName = fileInfos[randomImageIndex].FullName;

                //assign the random number to our session
                ViewState["RandomImageIndex"] = randomImageIndex;
                //assign the file path to our image control
                imagePlaceholder.ImageUrl = fullName;

            }

            this.Controls.Add(imagePlaceholder);
        }
    }
}