broken images - eviltoast

Hello,

Using the default web UI, sometimes post images don’t load, both for local and federated posts.

One example:
https://lemmy.world/post/20205083

Looking at the console, the requests to both the thumbnail and the main image fail with a 500:
https://lemmy.world/pictrs/image/45cab39c-d212-4581-bb8f-f9276e631531.gif?format=webp&thumbnail=256
https://lemmy.world/pictrs/image/45cab39c-d212-4581-bb8f-f9276e631531.gif?format=webp

The response body for both contains: {"code":"panic","msg":"Panic in blocking operation"}

Removing both parameters, format and thumbnail, returns the correct media.

Am I doing something wrong?