Email, Messaging, & Video Calls Email How to Add a Background Image to a Message in Mozilla Thunderbird Sometimes plain vanilla is just ... plain. Add oomph to your email by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on December 03, 2018 Hero Images / Getty Images Email Yahoo! Mail Gmail Tweet Share Email A white background in email is easy on the eyes, but the splendor of a colorful, classy, or artistic image is a welcome change now and then. In Mozilla Thunderbird, you can add a background image to an email that can be seen by the recipients of the message. Add a Background Image to a Message To add a background image to a message in Mozilla Thunderbird: Click the Write icon in Thunderbird and create a new message.Click on the message body.Select Format > Page Colors and Background from the menu.Click Choose File under Background Image.Select the desired file and click Open.Click OK. Tips When Adding a Background Image to Email If your recipients view their emails in plain text, the background is removed and they never see it. There's nothing you can do to prevent that. However, these tips can help you avoid pitfalls when choosing an image to place in the background of an email. Use an image that is stored on your computer. If you don't, it may be considered remote content and be blocked by default.Don't use an image you downloaded from a webpage. It may have hidden HTML or CSS code included when you copy it. The hidden code can affect the appearance of the email.Use a relatively small size image. This is not the place for gigabyte-size images.