About Magical Photography(( Magical photography, or moving photographs, has been prevalent throughout the Harry Potter series. It is only in The Chamber of Secrets, when Colin Creevy first meets Harry that there has been a hint of how these photographs may have been made. ))
Photography in the magical world starts with an ordinary muggle camera. It seems that only the oldest of models using film have been successfully bewitched to allow the creation of moving pictures.
In much the same way as an ordinary muggle film is developed, the film is opened in a dark room with chemicals (or potions) being a particular temperature. (( A step-by-step guide is available
here if you would ever like to refer to the methods. ))
The difference between the magical and muggle development methods is indeed that a potion is used rather than the chemicals that would traditionally be used. This potion has then has the effect of having the photos move once they have been developed.
It seems also that the subjects of these photos have the personalities of their real life counterparts. For example, if one were to be shy in real life, then their photo double may be inclined to hide off the actual photo.
"...a boy in my dormitory said if I develop the film in the right potion, the pictures'll move." - Colin Creevy (Chamber of Secrets, pg 75)
