I noticed that the "Import file" feature of the app extension seems to be a bit inconsistent:

When I launch the extension from the share sheet in the Photos app, the import option is hidden, while it is available when I launch the extension from Pythonistas own share sheet or an app like Transmit.

The problem seems to be that the photos app only specifies the public.png key, while pythonista itself (and presumably Transmit as well) specify the public.file-url key.

I think Pythonista should offer the "Import" option in both cases.

The "Import File" option:

The items passed to the extension: