To capture the image focused by the lens, digital photography uses an array of electronic photo-detectors, as opposed to an exposure on photographic film. The captured image is then digitized and could be stored as computer file for digital processing, viewing, digital publishing or printing. Usually made in CMOS technology, electronic photo-detectors are commonly used in cell phone cameras, web cameras and some other devices. Throughout this work, the author presents the linear simulation flow for CMOS Image Sensor Modelling he developed at IMEC research center. Int this purpose, he used MATLAB has computing tool and programming language. After describing the electromagnetic simulation of light propagation inside the pixel structure, the framework for the simulation of photo-generated electrons collection by photo-diodes, and subsequent Digital Signal Processing, a comparison is made between simulation results and ideal image sensors optical measurements. The accuracy and predictability of this methodology are demonstrated on various parameters which affect resulted pixels.