I would like to think that our integrated image host is better than external image hosts. Unfortunately pictrs (the app which uploads/serves the images) doesn't have the ability to run multiple instances yet. That is coming soon and should help a lot with these.
I would beg to differ on federating "better" but I might be biased π.
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.
I also prefer hosting externally and only linking the image directly in posts, avoids having the instance store additional files and has been pretty reliable and fast to me. I'd say something like catbox.moe or postimg.cc are good starting points -- from a general user perspective.
I also had an annoying experience where an instance purged their images and it resulted in me having to go back to my posts to update their files, since then I'm a firm believer in using external links instead, and this is never an issue in those cases.
Most of the time these errors are related to pictrs not responding fast enough. Usually because it has to convert the picture, video, gif and pictrs is already busy.
If you ever get these messages try again after 30 seconds (or so) and it should be fine
There is a correlation with file size. The picture I tried to upload was particularly big - about 20MB I think - so I probably should have downsized it anyway. There was no problem with uploading the few KB big screenshot.
20MB is the max size so it's probably an issue with file size rather than a timeout or something along those lines. It's interesting that our webserver didn't block the connection before adding it to pictrs.
If it works with a smaller image please let us know.
Iβd say reupload your image, and if you have more than one image, load the images in the description. Itβs faster and wonβt give you as many errors.