Wireless multimedia sensor networks (WMSNs) are networks of interconnected devices that allow retrieving video and audio streams, still images, and scalar data from the environment. With the ability of providing enriched observation of the environment, WMSNs can enhance a wide range of applications such as environmental monitoring, industrial process control, traffic enforcement, and advanced health care delivery. Most of these applications require the sensor network paradigm to be re-thought in view of the need for mechanisms to deliver multimedia content with a pre-defined level of quality of service (QoS).