I'm preparing to send mass email to customers which is in html + images. What are general rules to do make it display correctly in most popular mail clients?
EDIT:
Well it's for my customers - about few k clients.
My question is - how to code this email that it will display correctly in customer mailclient(thunderbird, outlook, gmail). What css tags can I use?
These two references are great places to start
Apparently using HTML 3.0 compatible tags and formatting works best for all email readers and providers.
I asked a similar question What is the best method for formatting email when using System.Net.Mail