Hello Charles
The Ministry of Information was a specific department created briefly at the end of the 1st World War and resurrected again during the 2nd World War, it was the central government department responsible for publicity and propaganda and as such all information issued was intended for public consumption.
Therefore you should have no problems using the information unless as Colin says the specific images are currently being marketed by an official organisation, a quick search on the interweb should be sufficient to answer this question.
Paul