Do you also have image upload issues sometimes? I have posted a screenshot of how it looks when it fails. It is a known bug -> https://github.com/LemmyNet/lemmy-ui/issues/1489
Do you maybe know how to get around it, and still be able to upload the image?
If you use a outside image host, your host instance doesn’t need to process the image for federation, it just federates a link some instance admins just set up a file hoster for example.