Hi,
Attachments, when clicked and opened, are downloaded to a temporary storage location. (e.g. C:\Users\<user>\AppData\Local\Packages\TimoPartl.Diarium_<someCode>\TempState\<filename>
in the case of the Windows app)
However, if they are modified, they are not uploaded back to the Diarium entry. It would be reasonable to be able to offer this possibility.
FYI, I am using Diarium on Windows and Android.
Thank you for reading me, and best regards.
Joan