Email marketing glossary

Email attachment

Email attachments are files sent within (or attached to) emails. These attachments could be PDF files, images, and more. However, some inbox service providers (ISPs) flag large email attachments as spammy behavior, causing emails to directly land in recipients’ spam folders or bounce back. This negatively affects senders’ reputation and email marketing metrics like conversion rate, open rate, and click-through rate.

Brands usually include documents like bills, receipts, or invoices as email attachments, while individuals might send contracts, documents, or images. Attachments are almost never used in traditional email marketing.

Learn more about how email size affects email deliverability, some ideas for email marketing automation, and how to maximize an email content strategy.