Picture receivers, also known as retinae, are devices that capture and process visual information. They are used in a variety of applications, such as cameras, microscopes, and telescopes. Retinae are composed of light-sensitive cells that convert light into electrical signals, which are then processed by the device. These signals can be used to create an image or video, or to measure the intensity of light. Retinae are essential components of many modern technologies, and are used in a wide range of industries.