In order to use a picture of a celebrity of model you have to ensure the picture is copywritted to the person who too the photo, this is standard unless the picture is classified under creative commons, and can be used for anything by anybody.
Pictures of people who are dead must have permission from their estate to be used unless they've been dead for 50 years or more.
If a magazine or company use a photo of a model or celebrity they must pay for their perimission to use the picture as well as the agent.

If the picture is of a child that parental permission is standard.