—We address the problem of modeling and adapting JPEG to the energy requirements of Visual Sensor Networks (VSN). For JPEG modeling purposes, we develop a simplified high-level energy consumption model for each stage of JPEGlike scheme, which can be used to roughly evaluate the energy dissipated by a given visual sensor. This model is based on the basic operations needed at each stage of JPEG, and it does not take into account the complexity of implementation. For JPEG adaptation, we propose to process only a reduced part of each block of 8 × 8 DCT coefficients of the target image, which minimizes the dissipated energy and maximizes the system lifetime, while preserving an adequate image quality at the sink.