Edit: Failed to redeploy /pub/static. All is now well in the world.
Followed docs @ https://devdocs.magento.com/guides/v2.3/frontend-dev-guide/templates/template-email.html#customize-e....
Magento ver: 2.3.5-p1 using custom theme
In place are:
<img> tag inside header.html:
Any edits to header.html work fine (adding a line of text, for example), but it's not grabbing my custom logo. Any suggestions?
Please follow steps to update email logo :
1. Go to Admin sidebar, Stores > Settings > Configuration. 2. On the Admin sidebar, Content > Design > Configuration > Select your current theme > . 3. You can see the existing design configuration on the management table, then click on Edit under Action. 4. On the workplace, please scroll down to Other Settings, open Transactional Email setion 5. Now for change Logo of Email, click on Upload to choose one of the image files you want to aplly for your logo.Enter the alternate text identify the Logo Image Alt.
It may help to resolve your issue.
If issue resolve, please click on 'Kudos' & Accept as Solution!
Already solved. See edit in OP.