A raster image is a rectangular grid of pixels. Its file size depends on the pixel count and colour depth, and enlarging it makes the pixels visible.
Raster graphics
An image stored as a grid of pixels, each with its own colour.
Related articles
termAlpha channel
An extra image channel that defines the transparency of every pixel.
termDPI
Dots per inch: the pixel density of a scan or a print.
termLossless compression
Reducing file size while keeping the data byte-for-byte recoverable.
termLossy compression
Shrinking a file by discarding data the eye barely notices.
termRGB
A colour model built from red, green and blue channels — used by screens.
termVector graphics
An image described by curves and shapes instead of a pixel grid.
termVectorization
Building vector outlines from a raster image.