The aim is to best utilize what WordPress already has in place, simply displaying images, captions nicely formatted showing up underneath images, sort of as it is now but nicer looking. That is what the site owner wants.
The plugin being used now is Lightbox Gallery by Hiroaki Miyashita with part of its css disabled since it caused the captions to only show up when hovering over the image. Thanks.
(It’s my mother’s charity website. I’m going to be refurbishing the whole site).