no more than 650 pixels wide
225k combined file size, all components (html file plus any images)
- no flash or embedded video
- image-only emails will be rejected, as they trigger spam filters
- emails should have 60/40 text-to-image ratio (text in images does not count towards the text ratio)
- should be tested to view properly in Gmail for desktop and mobile, as well as any version of Outlook for Windows or Mac, version 2007 and newer
- email should be responsive html to ensure it is easy to read on mobile devices. It is highly recommended that those who are unfamiliar with coding for email blasts use one of the templates available from Email on Acid. Click here to view their templates (May require a free registration).
We recommend reading this short article on ways to ensure your email will be delivered properly, and not flagged as spam. This article also has tips for making your email look as similar as possible across multiple platforms on multiple email desktop/mobile apps or web apps.