Systems and methods for authenticating transactions from a mobile device are described, including authenticating a user and a merchant location. A remote server receives an authentication request from a point-of-sale device, and requests that a user's mobile device use an associated camera to take a picture of the user at the merchant location. The remote server then processes the picture to determine the authenticity of the user and the location, and provides an authentication approval or denial to the point-of-sale device, instructing the point-of-sale device to execute, or not to execute, the transaction.