Image info uploads fail

[Megachile]

It's currently possible to add and delete images without errors, but any attempt to add or edit the attribution info gets the Uh-Oh error:

This isn't a spurious error message like we're seeing elsewhere; the information is not in fact added or edited after a refresh.

[Megachile]

This is what was printed in the console before the error info printed in the message above:

Failed to load resource: the server responded with a status of 401 (Unauthorized)