InsaneJournal

Level: Post Hogwarts Intermediate
Subject: Hogwarts Magic

Hogwarts paintings are practically full-fledged Beings. They speak and interact, not just with the humans in the castle but even with each other. These portraits were not created by the subjects themselves, but by an artist who created the painting during their life. The process includes a specific "imprinting" period where the subject occasionally visits the portrait to impart memories and other personality traits to the portrait. The artist cannot take credit for portraits that interact and display complex personality traits — it depends on the magical power of the person in the painting. ~ Lexicon

Game Canon
+ Single portraits have more personality than group portraits.
+ Single portraits can form their own memories & opinions
+ Painting subjects can jump from portrait to portrait
+ Frames can be silenced - not the subject in particular.
+ Paintings are protected with a ward to prevent jinxes