All emails are hand-made or heavily edited base templates. Once the original template is made, content (including graphics) is swapped to keep design on-brand and relevant to the goals of the email. All emails are fully mobile-responsive, working and displaying the same in every email client.
Every link in the email is individually tracked and measured, along-side open rate. By tracking these metrics, continual improvements (particularly to the banner image) led to dramatically increased open rates over previouslu used email solutions.