1. A camera device comprising: an image sensor; a memory; a processor for processing images; wherein the camera device is adapted to be wearable by a human subject in a manner that images captured using the camera device represent surroundings of the human subject; wherein the camera device is operative to process images captured using the camera device for detection of an event, the event being an action of the human subject, the event being detected by performance of an image processing method that includes a comparison of a subsequently captured image to an earlier captured image; wherein the camera device is operative to wirelessly transmit a message to an external destination responsively to the detection by the camera device of the event.