Lightbox Images are always cut off in pop-out modal

I’m at my wits end trying to get a Lightbox to display properly on my site. No matter what I do, when the user clicks the lightbox link and the lightbox modal appears, the image within is offest, causing it to be cut off at the bottom. I’ve tried every Overflow and Sizing option I can find in the editor and I’ve tried making smaller images. Even at 500 x 500 px, the images are still being shifted and cut off.

How do I get the lightbox modal to contain the whole image?

Here is my site Read-Only: LINK