A filter is a special kind of tool designed to take an input layer or
image, apply a mathematical algorithm to it, and return the input layer or
image in a modified format. GIMP
uses filters to achieve a variety of effects and those effects are
Most filters have a Preview where changes in the image are displayed, in
real time (if the “Preview” option is checked), before
being applied to the image.
Figure 16.1. Preview submenu