Solution for pop-up size?

Hi there!

First of all, sorry for my poor english. So, i have a page (http://efi.szakrendelo-sarkad.hu) where i have NextGen Gallery (up-to-date). When i like to display my images, click on the thumbnail but the pop-up doesn’t shows my image full sized. Its resize it to fit on the page. How can i solve this? Like “scrollable” pop-up?

Problem ex: http://efi.szakrendelo-sarkad.hu/?p=582

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