Size of popup images

How do I resize the images in the popup to full size?

Steps:
1. Added a gallery to a page with these settings:
[gallery show_title="0" type="photosbox" size="full" ids="68,67,66"]
2. Saved changes and viewed the page
3. Clicked one of the images.
Expected result: slide show with images at 100%
Actual result: slide show with images at thumbnail size and descriptions under the images have overlapping text.

Thanks

https://www.ads-software.com/plugins/photos-box/