<img src="GeneratePicture.ashx" />

    public class IISHandler1 : IHttpHandler
    {
        /// <summary>
        /// You will need to configure this handler in the web.config file of your 
        /// web and register it with IIS before being able to use it. For more information
        /// see the following link: http://go.microsoft.com/?linkid=8101007
        /// </summary>
        #region IHttpHandler Members

        public bool IsReusable
        {
            // Return false in case your Managed Handler cannot be reused for another request.
            // Usually this would be false in case you have some state information preserved per request.
            get { return true; }
        }

        public void ProcessRequest(HttpContext context)
        {
            //write your handler implementation here.
        }

        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

<%@ WebHandler Language="VB" Class="WebApplication1.GetCameraScreenshot" %>

namespace WebApplication1
{
    public Class GetCameraScreenshot : IHttpHandler 
    {

        bool IHttpHandler.IsReusable 
        {

          get 
          { 
            return true; 
          }

        }

    void IHttpHandler.ProcessRequest(HttpContext context) 
    {

      // handler code

    }

  }

}
	

<img src="GeneratePicture.ashx?id=12345" />