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.
