The evolution of image sensors and the prospects utilizing advanced imaging technologies promise to improve our quality of life. The image sensor application is expanding to mobile devices, wearables, medical solutions, security networks, factory automation and autonomous driving while drastically accelerating the performance improvement and enhancing the functionality of imaging devices by stacking technologies. This talk introduces a broad overview of the key device technologies for image sensors, as well as circuit techniques, image signal processing and performance characteristics, that enable imaging applications in various fields. The next challenge of imaging system will be discussed for future society, where the imaging devices are integrating the extended sensing capabilities of spatial depth, temporal dynamics, invisible light, and inference.