Consent and Privacy
The question of when a person's permission is required to photograph them and to publish the result.
In depth
Law varies widely: some countries permit photography of anyone in public, others grant a right to one's own image that restricts publication regardless of where the picture was made. Beyond law, ethics asks about vulnerability and power — whether a subject could meaningfully refuse, and whether publication exposes them to harm.
Examples in practice
A street photograph legal to make in one country cannot be published in another without the subject's written permission.