Adobe Portfolio photo grid option...

Hi to everyone, i'm starting getting my photography website and wanna ask how it is called the function where when you pass the mouse over a photo in a grid (ex in the home) the photo change and show another image? I've updated some photos to the grid in home but don't find this option. I see it in examples profiles , here: https://chrislukesmyth.co.uk

Look his Home, pictures change where mouse pass by.

What can i do to do this with Portfolio?

[Moved from Community Help (which is about the forums) to a better forum... Mod]

Thankyou

Fabio