As with most Windows programs Repligator has the normal copy and paste functions. You can copy an image from your paint program, and paste it into Repligator, for example. But there is also a function called "Internal Copy and Paste", and this is its icon:
What this does is take the current image you are working on and paste it into a new window, allowing you to apply another effect to it. Here is an graphical example of the idea:
So it is simply a quick way of applying two effects to an image.