Many would like to believe it. If it is her, then it will be one of the most surprising things you will ever see. OK, it was taken in 1840, when Wolfgang was long gone. Few wives outlived their husbands. Given the harshness of the times, she hardly looks 78.
As Sean Munger comments, Constanze became the Yoko Ono of the 19th century. Wiki also cites the Grove dictionary:
Early 20th-century scholarship severely criticized her as unintelligent, unmusical and even unfaithful, and as a neglectful and unworthy wife to Mozart. Such assessments (still current) were based on no good evidence, were tainted with anti-feminism and were probably wrong on all counts.
* * *
If only we had photos of the Li family Daoists (and their wives) from the late imperial era… Even the photo of Li Peisen and his wife from the 1940s is rare enough. Indeed, in a world where female members of a family are taken for granted at best, people remembered her as exceptionally able and intelligent too.