images in gallery pop up in new window but i would like them poping up lightbox style in the same window


Hi, i am Alois and i am new here.
I have bought a nice template from themeforest. “Simple transitions Portfolio”.
This template uses the mootools library.
My Problem is that the Images in the Gallery opens all in a new window but i would like to
open the Images poping up in the same window like lightboxes do. In the short disrciption stands that i can make the Images poping up with modal but i do not know how to do that. I would be very glad ift someone here could help me. Thanks in Advance.