PICTURES AT HOGWARTS

[jennifer]

No: HPFGUIDX 176666

In all of the books the pictures can visit other pictures at Hogwarts.
Case in point when the Fat Lady's friend Violet visits her after the
announcement of the Triwizard Champions in the Goblet of Fire or Sir
Cadogen running throught the portraits to lead Harry, Ron, and Hermione
to the Divination tower in The Prisoner of Azkaban.  Why couldn't
Dumbledore visit Phinellias Black's portrait in Deathly Hallows?  He
said that they could commune with each other but that he could not
bring Dumbledore into his portrait.  This is very confusing because if
other paintings could visit each other then why couldn't the
headmasters not visit each other's pictures?

Jennifer