1. A monitoring system comprising: a camera unit that is configured to capture images of an area in a monitored property and that includes a passive InfraRed sensor that is embedded in the camera unit and that is configured to measure InfraRed light radiating from objects in the area in the monitored property; a remote monitoring server that is located remote from the camera unit and that is configured to process image data captured by camera units associated with multiple, different customers of a monitoring company; a gateway that is located in the monitored property and that is configured to communicate with the camera unit using a short range wireless protocol and that is configured to communicate, over a network, with the remote monitoring server; and at least one processor of the camera unit configured to perform operations comprising: detecting a motion event based on output from the passive InfraRed sensor that is embedded in the camera unit; in response to detection of the motion event based on output from the passive InfraRed sensor, controlling the camera unit to capture one or more images of the area in the monitored property; and transmitting, from the camera unit to the gateway, the one or more images captured by the camera unit; and wherein the gateway is separate from the camera unit and configured to perform operations comprising: in response to receipt of the one or more images captured by the camera unit, accessing a security system rule that controls whether the one or more images captured by the camera unit are transmitted to the remote monitoring server based on detecting activity in the monitored property that confirms the motion event detected based on output from the passive InfraRed sensor; comparing one or more sensor events to the security system rule to assess whether activity that confirms the motion event has been detected in the monitored property after the camera unit captured the one or more images, the one or more sensor events being sensed by one or more sensors that are different than the passive InfraRed sensor; based on the comparison of the one or more sensor events to the security system rule, determining to transmit, from the gateway to the remote monitoring server, the one or more images that were captured by the camera unit in response to the motion event; and based on a determination to transmit the one or more images captured by the camera unit from the gateway to the remote monitoring server, transmitting, from the gateway to the remote monitoring server, the one or more images captured by the camera unit.