Look for attachments in both database and filesystem
Setting HYPERKITTY_ATTACHMENT_FOLDER
seems to currently make HyperKitty unable to find attachments already stored in the database. As there does not seem to be a way to export attachments from database to the filesystem, this setting can not be changed on an existing list.
It would be better if HyperKitty checked whether hyperkitty_attachment.content
is not null, before checking the filesystem for attachment.