Jaggies is an informal slang term used in digital photography and image editing to describe the visually unpleasant staircase-like or saw-toothed edges that appear along diagonal or curved lines in a digital image. They are caused by the inherently square, grid-based nature of pixels, which are unable to represent smooth diagonal or curved edges with complete accuracy, resulting in a stepped appearance that becomes particularly noticeable when an image is viewed at large sizes, heavily cropped, or printed at low resolution.
The visibility of jaggies is directly related to the resolution of the image and the size at which it is displayed or printed. At higher resolutions, where individual pixels are smaller and more numerous, the stepped edges become finer and less perceptible to the human eye. At lower resolutions, or when an image is enlarged beyond its native pixel dimensions, the individual pixels become larger and more visible, making jaggies increasingly pronounced and distracting.
The primary technical solution to jaggies is a process known as anti-aliasing, which works by introducing partially transparent or intermediate toned pixels along edges to create the visual impression of a smoother transition between contrasting areas. Anti-aliasing is widely applied in image editing software, digital cameras, and display rendering engines to minimise the appearance of jaggies and produce cleaner, more natural looking edges. Many cameras also incorporate an optical low pass filter or anti-aliasing filter in front of the image sensor for a similar purpose, though some manufacturers omit this filter to maximise fine detail resolution.