Depends on whom you take a photo off, where and from where.
It's a complicated matter juristically, but the morale is easy. Don't take a photograph of someone visible in your photo without their consent. If so, at least don't upload it anywhere public or online.
In Germany there's a law giving you the copyright on your own photo[1], it's difficult in the USA and less difficult in other countries[2]
EDIT:
Voice recordings are practically illegal in the public without consent in Germany[3] and also in the USA [4][5].
From [2]:
"Should the subjects not attempt to conceal their private affairs, their actions immediately become public to a photographer using normal photographic equipment."