term

Alpha channel

An extra image channel that defines the transparency of every pixel.

Alongside colour, each pixel stores an opacity value. PNG, WEBP and TIFF keep the alpha channel; JPG does not, so transparent areas are filled with a solid background.

Related articles

formatPNG

PNG file format: extension, MIME type and available conversion directions.

termRaster graphics

An image stored as a grid of pixels, each with its own colour.