Photographs vs Portraits

[Cat]

No: HPFGUIDX 183185

Greetings All!

If this query has been answered previously, I apologize for asking it
again. But, I do need some helpful insight from HP scholars! A friend
of mine who is reading the books for the first time asked me a question
that had not occured to me ... Why can paintings/portraits move, talk
and interact(they have sentience), whereas photographs only move but
not talk (just amimated images)?

Is there anything in canon or from a JKR interview that might shed
light on this?

Or maybe one of you could help me out with a theory?

Thanks!
Cat