Originally Posted by monkeybreath

If you view the image in the email (normal a 1 x1 pixel clear image) then you effectively visiting the spammers site; if i sent you an email with an image for example www.mydomain.com/image.jpg and you viewed it, the html would cause your email client to access www.mydomain.com/image.jpg to download the image. The spammer can then view the logs on their server to see the ip addresses that have accessed the site. I am sure they have programs that can automatically log this and so the spamming continues...

hth
MB

Originally Posted by cichlid

I'm all for fighting back. Check the headers of the email and send it back where it came from (if you can). You'll find their ISPs have an acceptable use policy similar to NTLs which, if you read it, says they're not allowed to do that.
I realise this isn't possible for all of them but I think the attitude of just using spam filters ensures that problem continues to linger. If you think about it, they are actually stealing our bandwidth. Any ISP that receives a message regarding 'theft' isn't going to ignore it.
Hey if NTL can consider uncapping your modem as bandwidth theft then I can regard spam the same.