Picture pixels in the case of the Paint module are the actual graphic data, which can be changed by the tools. Under strong magnification they can be recognized as square or rectangular areas, from which the picture is ultimately made up.
Each picture pixel processed by the Paint module can assume 256 different levels of intensity in each colour plane. Greyscale images have only one plane: the brightness; with RGB pictures there are three (Red, Green and Blue), with CMYK four planes: Cyan, Magenta, Yellow, and Black (also called contrast (K) or depth).
Each picture in a document requires one byte per pixel for storage in a greyscale picture, and four bytes per pixel for an RGB or CMYK picture, to store the intensity values.
