I want to track Email if opened by user and increase the count in my database.

**I have tried a lot a things like image sending and bgsound but none of them worked. But now i will do with the help of image sending. I am not getting the idea of how to send a callback to the database to increase the count in database **

I dont want the whole exact code or program just the idea or some lines of code which can help me out .

Each email embed a small image maybe one pixel wide, behind that image add a href with a unique that calls your server. That tells you if the email has been viewed.