Lighbox Plus not working with Sandbox theme

I have tried multiple Lightbox style plugins with Sandbox and they all seem to not work to varying degrees. When I am using a different theme I have no problem getting Lightbox Plus to work on the WP Gallery images but with Sandbox the images go to the image.php template instead. Currently the images that I have inserted into the post call up Lightbox just fine, so I assume it is a problem with the theme but I have no idea where to start.

My site is https://bvgphoto.com/blog.