CS > The Alter Rebbe paskens you can’t daven to a picture (even a mirror is bad),
a good point. For those who do have rebbe’s picture in front of them:
if a chosid can daven in front of a picture, then the rebbe should be able to daven in front of a mirror. Is there any evidence that Rebbe davened in front of a mirror? I have a proof that he did not: when Chabad built first girl’s seminary, rebbe came to inspect the building and he suggested one addition: put mirrrors in each room. Evidently men in charge of construction did not think about it. Which proves that there were no mirrors in the rest of 770 complex. See, I can see the lack of mirrors without ever coming inside!
PS As someone telling a story of Hasam Sofer visiting newly built Vienna shul and commenting on construction remarked: “for some reason, all these stories have a Rav visiting after construction instead of being asked in advance”. So much for daas Torah… Of course, this could be selection bias – only mistakes become stories; shuls built according to daas Torah have no stories attached.