Learn in the textbookFile Formats for Still Images and Documents
DefinitionGIF is a still-image format that limits a single image to at most 256 colors and stores it with lossless compression that causes no degradation.
ExplanationThe colors in use are first gathered into a color table (palette) of no more than 256 entries, and each pixel is stored as an index into it. Low-color icons and graphics can be saved small without loss, and a file can also mark one color as transparent or switch between several frames for a simple animation.
AnalogyIt is like filling in a coloring book with a chosen set of up to 256 colored pencils. That is plenty for a picture made of flat colors, but a photo of a gradient sky can only be approximated with the pencils you have.
Memory hookIt stands for Graphics Interchange Format, and it was first built to exchange (Interchange) images over early online networks.