If you have upgraded from an earlier version of Magento Open Source, you can use an email client to view each transactional email template that is generated by your store. Verify that the logo, fonts, and styles render correctly. Email templates that were created with earlier versions of Magento do not have the
non_inline_styles variable, and are not responsive. However, most can be used as they are.
To take advantage of the high-resolution display that is available on many devices, email logos are now uploaded at twice their display size. If you intend to use the responsive email templates, you should upload a higher resolution logo.
It is not necessary to reconfigure your email logo for use with custom templates that were created with earlier versions of Magento.