Jaggies

Jaggies are artifacts in raster images, most frequently from aliasing,^[1] which in turn is often caused by non-linear mixing effects producing high-frequency components, or missing or poor anti-aliasing filtering prior to sampling.

Jaggies are stair-like lines that appear where there should be "smooth" straight lines or curves. For example, when a nominally straight, un-aliased line steps across one pixel either horizontally or vertically, a "dogleg" occurs halfway through the line, where it crosses the threshold from one pixel to the other.

Jaggies should not be confused with most compression artifacts, which are a different phenomenon.