I am trying to set my own logo in transactional emails. When I upload the logo in:
CONTENT > Design > Configuration
the preview is correct, but then save, the page reloads but the logo is broken, link points to:
which is wrong in my opinion.
I guess you're talking about this bug:
MAybe this comment will help you: https://github.com/magento/magento2/issues/5352#issuecomment-249351661 (I didn't test that approach)