An image sensor is a device that converts light into electrical signals, allowing cameras and other imaging devices to capture pictures. There are two main types of image sensors: CCD (Charge-Coupled Device) and CMOS (Complementary Metal-Oxide-Semiconductor). Each type has its own advantages, such as image quality and power consumption. Image sensors are commonly used in various applications, including digital cameras, smartphones, and medical imaging devices. They play a crucial role in determining the quality of the images produced, influencing factors like resolution, color accuracy, and low-light performance.