The data discarded is in most cases beyond the ability of the human vision system and thus there is no discernible difference between the original image and the compressed image. A 640 X 480 monochrome image would require 38.4 KB of storage. Where the value represents the shade of gray of the pixel. A 640 X 480 grayscale image would require 307.2 KB of storage. The size of a color image depends upon the number of shades of each primary color that is stored.
Monitors are capable of displaying millions of colors.
This yields acceptable color quality, but does not compare to 35mm photographic quality. A 640 X 480 24-bit color image would require 921.6 KB of storage. The extra byte of data for each pixel is used to store an alpha value representaing special effect information. This format is used primarily for storing graphics produced with technical drawing pograms. Although some method for imbedding a bit-map as part of the image is usually provided.