Yes. I want to create a mail server that auto-rejects e-mail with externally hosted tracking pixels and returns a Mailer-Daemon error that tells the sender to re-send without malware.
Of course with Gmail I disable automatic image loading to avoid being tracked, but I want to take a more active stance against the practice.
I would just block all images loaded from external URLs, since any of them could be used for tracking, but the newsletters are less my concern, it's more the individuals that I would be concerned about, and they tend to be a almost-fully plain text e-mail with a 1x1 image from one of many well-known domains for tracking.
Emails can have "inline" attachments, where an image can be attached in the body of the email itself. So the image shows up without any network access, but it's generally base-64 encoded (costing 4x space) and ends up using a lot of email storage space.
Ohh, I was thinking 256/64 = 4x, but it's apparently it's 8 bits / 6 bits = 1.3333x. Thanks. Plus for email a little extra for a =\r\n on every line, so more like 1.4x.
If you do this you might not be able to go on a "paperless" billing plan with your bank or insurance company. I disable images too but financial institutions interpret "no tracking image requests" as "client's email address doesn't work" and they start mailing me paper again. Took me years to figure out the reason for this brain-dead lossage.
That's their fault then, I'll start returning their postal mail as undeliverable and if they give me further troubles I'll find another institution to do business with.
Of course with Gmail I disable automatic image loading to avoid being tracked, but I want to take a more active stance against the practice.