Digital image of a microfilm where original researcher can't identify provenancee

I have in my possession a digital image of what is clearly a microfilm image of a 'Statistical Return of Marriage' in Quebec Canada for a marriage that took place in 1927; it was provided by a distant cousin who can't remember its proveance.

These documents are not now available online (although they may have been previously) and 3200 miles is a long way to go to consult the microfilm; copies can only be ordered by people named in the document (for privacy reasons).

How should I cite the image I have? As a digital artefact from the private holding of my cousin?  Or, as it was supplied to me in an email, shuld I cite the email?