2 Won't work any more now that Google have led the charge with downloading images in email messages to their own servers and serving them to users themselves.

2 Won't work any more now that Google have led the charge with downloading images in email messages to their own servers and serving them to users themselves. I expect all email providers to follow Google's lead on that tbh because it's really quite good. 3 is a bit of a problem with residential broadband as IP address get re-assigned a fair bit.