The images we “see” are perceived by millions of optic nerves and each of them “captures” a tiny fraction of the image and stores it.
In a camera the “frame” quality depends on the number of points used to store the image. These points are the pixels, which form the electronic film of the camera.
The CCDs (Charge Coupled Devices) are usually small in size, 5x7mm for example, and contain thousands, millions of pixels depending on the the instruments quality.