How to know weather someone opened my mail?

I'm sending mails from my site. I want to now that this mail was read or not (oponed)
I've tried 3 methods:
- <img SRC="www.domena.com/mail_read.php?id=id">
- <scritpt src="www.domena.com/mail_read.php?id=id">
- <img SRC="www.domena.com/mail_read.gif?id=id"> (404 error site where database is updated)

NON of this method was 100% successful (Outlook is my wors enemy )

Is there a way to do that? How Google does it (in Analytics it has that option - http://www.google.com/support/analytics/bin/answer.py?answer=27249&query=gif%3F&topic=0&type=f )

 

there are plenty small cheap cgi scripts out there free and some for small fee that do that for you.

 

what cgi scripts? Are they 100% sure?
Can you pass me some links to tried ones?

 

there is no 100% sure way.
I for one do not allow my emails to render html.

 

I think you can't have 100% firmly statistics of mail display. You can only know how many subscribers click on links in mail.

 

make a php script That uses the GD library to make a small 1x1pixel image

ok

now in your email link to that image

<img src="http://yoursite.com/imageGenerator.php" />

now every time the email is opened, that 1x1 pixel is created, also the same imageGenerator.php can have few lines of code that increment a counter in database everytime the script is called

 

Yeh I once developed a system to allow show webmasters stats on who viewed their emails.

It went very well using the php GD image method, but the problem is that many people (myself included) never send out HTML based emails, since it is despised by recipients... so it will only work in a minority of cases...

 

I see that not only HTML is problem.
Outlook for example don't allow to view img from a server (http://www.s.com/mail.gif)
You have to click show button.
So there are no 100% sure methods