is any of a series of unwanted variations that appear in a digital camera photo. Noise appears as strangely colored or grainy pixels in a photo, especially as purple edges to objects, called purple fringing. Noise in a digital image is especially common in photos shot in low light.
Noise occurs because of electrical variations and interference in the image sensor. High ISO settings can create noise.
Although they have the same results, noise is not quite the same as artifacts, which are digital image distortions caused by JPEG compression techniques.