This work is in the public domain in Portugal because it is one of the following:
A photographic work, work deemed to be photographic work or work of applied art created before 1 July 1970 (more info here); or
Another type of work whose author died before 1954; or
An anonymous work or a work deemed to be anonymous, or a work by a collective person whose authors were not individually identified, published or disclosed before 1954.