I am using vb.net to send email to user along with image. I embedded page name under image
You can create a custom HttpHandler along with a distinct file extension for the new HttpHandler to handle. This way when a request comes into the web server with that extension you can do your processing either with the file name or any parameters passed along.
There are many articles regarding custom HttpHandlers on the web. Just google it.
Remember, that for your solution to work the end user must have an open connection to the internet. Some email viewers are also not displaying images...due to the "security" risks involved. What you are trying to do...sounds like a "spam" technique to me.