As noted, the image is indeed available through the official website for Canada’s museums. It was part of the exhibit “Their Past Lives Here” from Bralorne-Pioneer, available to the public since 2004. It was put online since February this year, perhaps before that. And the peculiar “time traveller” image was only noted as such in the end of March, when it was linked on main websites such as Above Top Secret and FARK.
Given the source, we would assume the photo is authentic, and correctly dated to c.1940. Indeed, an Error Level Analysis suggests the image was not digitally tampered with, or at least that if it was, the author was smart enough to normalize the error across the whole thing. It’s a good job, if it was a job. And again, given the source, we would assume it was not a job.