Electronic imaging systems based on solid-state image sensors have received tremendous attention in the past few years. The many advantages of the solid-state image sensors have opened up a wide variety of new imaging possibilities. Applications, ranging from high resolution, spaceborne electronic camera to PC peripheral camera, were costly, it not impossible, using the earlier technology. This paper will describe the technologies of charge-coupled device (CCD) and CMOS image sensors. A review of the recent advancements and industry trends will be given. Challenges in sensor performance, device scaling, and fabrication processes will also be discussed. The paper will conclude with a description of some applications and opportunities for the solid-state image sensors.