What is the best way to attach images to email in php?

Question

PHP

Good afternoon, friends, I am writing for my store a class for sending letters to the buyer, with dubbing of his purchase.
The question is, how best to attach the store logo and product images. As an attachment or just give a link to your server and mail services, then they themselves re-cache, because I looked in my mailbox, all the pictures are all exactly cached.
What's the best way to do it? And if someone shares a link to the ideal script to send, I would be grateful.

Answer 1

Absolute links. No attachment! Only HTML emails!!!
All this is made up for mailing and you just send the HTML code.