The dealer to whose site you've linked is offering the same photo on Etsy- that's where I bumped into it. Though the dealer identifies the lady in the photo as McAvoy (1899-1984), I don't think it looks much like her, and, for the 50-ish woman in this photo to have been McAvoy, the portrait would have to have been taken when the
Witzel studio no longer existed. But I most certainly could be wrong, as my eyes are, increasingly, for the most part, shame-faced liars.