Gallery images cropped issue

Hi,

I have a page with an image gallery here:
http://irishcountryimages.com/index.php/nggallery/slideshow?page_id=592

You will see when any image is clicked the top of the expanded image is cropped.
How can I reduce the size of the expanded images to avoid this?

Thanks
Andy

https://wordpress.org/plugins/nextgen-gallery/