This may be linked to the recent update since I posted something two days ago without problem, and I saw to other users commenting about the same problem on the upgrade post. It is not an app specific problem: Eternity just says "Error: 400" when trying to post something with an image, but if I use a browser (tried with both Mull on Android and Firefox on Debian), I get the following error:

{"data":{"error":"unknown","message":"Request error: error sending request for url (http://pictrs:8080/image): error trying to connect: tcp connect error: Connection refused (os error 111)"},"state":"success"}

I hope this is the correct place to post about it, sorry if not. Have a good day!