Slideshow Plug-in with Wide Screen Template

Howdy.
I am using Wide Screen from Graph Paper Press. I want to built slideshows of my photography portfolio.
Like this one: https://www.melissaschilling.com/little-people-3/

I added the slideshow plug-in and just want to make the images bigger. Does anyone know the largest height/width I can set for this template with this plug-in?

Thank you!