Repeating an earlier post that became corrupted.
The UK, Wartime Records and Material, 1914-1918, 1939-1945 collection, just added by Ancestry, is from the IWM’s holdings of wartime materials, including films, photographs, and maps, as well as newspapers, journals, and other miscellaneous printed materials, such as tickets, leaflets, and posters.
There are 5,143 items in the Ancestry collections so far. More are likely to be added.
The image above is one of six hits searching the word Canada, found because the caption mentions the large number of Bomber Command crew who were Canadians. You’re unlikely to find a family member mentioned, very likely to find an image to illustrate a UK wartime activity.