An update on this topic:
- I’ve gone through the code, and confirmed that the avatar file is generated in a temporary location and then moved into place, which should mean it’s atomic and there’s no possibility of the file being empty at any point. The creation and move is all happening on one filesystem, too.
- I’ve greatly increased the amount of logging we’re doing on avatar service, so @Mittineague, if you get the problem again on any forum that’s using our letter avatars service, if you can give me a time (to within a couple of minutes) and the exact URL that misbehaved and then came good (and, preferably, the IP address you were using), then I should be able to see exactly what’s going wrong.