How to change the look of an object if a certain slide has been visited?

Hello all,

I have a navigation or overview slide with different icons (=images) for the chapters of the training on it. How can I change the look of the icon when the user has visited a chapter and returns to the overview slide? So the users know, which chapter they have allready worked through?

I'm using Captivate 8.

Thank's a lot for any answers, I hope I could make myself clear.