There are two types of image file compression algorithms: lossless and lossy.
Lossless compression algorithms reduce file size while preserving a perfect copy of the original uncompressed image. Lossless compression generally, but not exclusively, results in larger files than lossy compression. Lossless compression should be used to avoid accumulating stages of re-compression when editing images.
Lossy compression algorithms preserve a representation of the original uncompressed image that may appear to be a perfect copy, but it is not a perfect copy. Oftentimes lossy compression is able to achieve smaller file sizes than lossless compression. Most lossy compression algorithms allow for variable compression that trades image quality for file size.
Read more about this topic: Image File Formats
Famous quotes containing the words image, file and/or compression:
“Her image was my ensign: snows melted,
Hedges sprouted, the moon tenderly shone,
The owls trilled with tongues of nightingale.”
—Robert Graves (1895–1985)
“A common and natural result of an undue respect for law is, that you may see a file of soldiers, colonel, captain, corporal, privates, powder-monkeys, and all, marching in admirable order over hill and dale to the wars, against their wills, ay, against their common sense and consciences, which makes it very steep marching indeed, and produces a palpitation of the heart.”
—Henry David Thoreau (1817–1862)
“Do they [the publishers of Murphy] not understand that if the book is slightly obscure it is because it is a compression and that to compress it further can only make it more obscure?”
—Samuel Beckett (1906–1989)