Puzzle n°31 (**) - Beware the postman !

In this strange land, somalis can only exchange objects between them through postal services.
But postmen are all thieves without exception:
though they deliver the locked parcels correctly,
they steal systematically the contents of all parcels which are not locked.
If a parcel has one or more open locks, they even steal these locks !

Every somali has one armoured box and a lock with a unique key.
This key cannot be duplicated and it represents the only way to open the corresponding lock.
The boxes can be securely closed with one or more locks.

One day, Pomponnette wants to send pictures of her babies to Brownie.
How will they manage so that these pictures reach Brownie without being stolen by the postman ?

Pomponnette

Brownie

... I'm giving up ...