What is a magical photograph?
Wizarding photographs of people have similar properties to magical painted portraits: the figures within move about or even sometimes leave the frame. As with the paintings, the images of people in the photographs do not appear to age. Photographs from ordinary Muggle cameras can be made to seem alive. Colin Creevey mentions in Chamber of Secrets that a boy in his dormitory said that if he develops the film 'in the right potion', the pictures will move.
However, figures in Wizarding pictures do not reflect the emotions or actions of their counterparts in the real world. Moving photos also appear in wizard newspapers and other print media, as well as on Chocolate Frog cards. This is exemplified in Prisoner of Azkaban when pictures of Sirius are printed in The Daily Prophet newspaper. The magazine Witch Weekly also contains pictures of smiling and winking witches.
The images of people in photographs display little sentience. The subjects of some photographs can leave the frame, but no indication has been given that they are able to visit or communicate with other photographs or with people in the world, as is the case with their painted counterparts. However, it appears that they do have some knowledge of current events, as seen by Harry when he goes to Mr Weasley's office on Order of the Phoenix. The family photograph on Arthur's desk shows everyone except Percy "who appeared to have walked out of it".