The slider supports 5 differents modes on how the content will be overlayed.
Overlay
This is also the default mode.
[image-comparator method="overlay" ...][/image-comparator]
Fade-In


[image-comparator method="fade-in" ...][/image-comparator]
From-Right


[image-comparator method="from-right" ...][/image-comparator]
From-Left


[image-comparator method="from-left" ...][/image-comparator]
Side-By-Side


[image-comparator method="side-by-side" ...][/image-comparator]
Random
This is not really it method. It just selects a random one from the others.


[image-comparator method="random" ...][/image-comparator]