This command distorts an image using random method.
You can select type of deformation between following:
Ripples - this is the most smooth and gradual distortion simulating a reflection in a water with irregular ripples.
Erosion - this command distorts an image using the method of a random erosion.
Excitation - this tool lets you simulate a painting made with wide strokes.
The Size field sets an average size of the distortion while the Strength field controls how heavy the distortion is.
If you check Freeze button, the deformation will be the same from time to time with the same set of parameters. If you don't check this button, the deformation will be different from time to time.