Do you mean have more than 44 images in each slideshow?
I definitely would not recommend doing that or trying to change the theme to support it. As is, it takes over a minute for that page to load because all of those images have to load in.
I'm not really sure the slideshow can support that many. For better peformance, you may want to have the portfolio items set up to show 5-10 images for each event and then in the portfolio description have a regular wordpress gallery with additional images. That way the overview page like the one you linked to there loads up quickly and gives the user an opportunity to view more images without the huge load on your site and slow download on their end.