The answer is somewhat complicated, so a live consultation with an attorney is highly recommended. Generally it is not OK to use a photograph of another, for profit, without a proper release from the subject. It is also not OK to deliberately harm someone by the use of their photograph, in, for example, a libel situation in which a lie is told ascribing the lie to the subject. Photographs taken in public are not protected. You have no expectation of privacy on the street. So, the photograph may be 'legal' or OK. And republishing it is OK if no harm is intended or results.