Sensors are the less durable parts in any chemical sensor system, then the replacement of sensors maintaining hardware and data processing is a necessity in real applications. Though sensors replacement requires a perfect reproducibility of the sensors fabrication. Among the different sensor technologies, those based on optical transduction may offer a straightforward methodology to release the requirement of identical sensor manufacturing. In particular it will be shown here that the use of image sensor provides a surprising parallel with natural olfaction. An important consequence is that the data processing is independent from the geometric arrangement of the sensitive layer. This feature leads to a simple sensor layer replacement and to a prompt arrangement of different sensor systems, even remotely located, into a single data processing system.