Relying on images in email marketing can hurt you for a few reasons: 1) It can increase the likelihood that your email will be marked as spam, and, 2) because so many services such as Gmail, and email programs such as Outlook, automatically block images, it can be detrimental to the effectiveness of your email if much of the impact of it was visual. Even when email applications don’t block images by default, many users are being advised to disallow images in incoming emails.
