Open lightbox gallery from button

Hi there and thanks for the plugin, it is very versatile. Maybe someone could help me…

I would like to accomplished this: let’s create a gallery by using [su_custom_gallery source=”media: 578,579″ limit=”2″ link=”lightbox” width=”320″ height=”190″ title=”never” class=”whatever”]. It shows two small images and, when any of them is click, a lightbox opens with the image in it and the controls next / previous.

How would I add a button below the gallery to open that same lightbox gallery?

I’m thinking in some users that may think that the small images are only decorative. Having a button below may enforce them to clic it and open the gallery.

The page I need help with: [log in to see the link]