UJM,
Ok, you really want to hear what I gave to say on the matter.
The reason why I haven’t been answering is because I don’t really have much to say on the matter.
Why do Lubavitchers put up pictures of the Rebbe more then others?
I can’t really answer this because I don’t know any official shitah or Torah explaining this.
This is not an official Chabad movement, and not everything done by Lubavitchers is a Lubavitcher thing.
If you’re asking for theories, you can ask anyone.
Maybe it’s because Chabad in general does things in a more public way, like menorah lightings and lag baomer parades.
Maybe it’s because Chabad is more centered around the Rebbe than others might be with their gedolim (as it was throughout the history of Chabad).
But again, those are just theories, not written anywhere.
What is written in Torah I have already brought in my earlier post.