You’re welcome to use the built in gallery if it helps you out. It’s built to make use of WordPress’ native gallery feature. There’s a video on the home page of our support site if you haven’t used it before.
The lightbox will be used on any link that points to an image file. However, the previous/next arrows will only appear within a gallery, so if you need to have them present, you’ll need to use WordPress’ galleries.
The captions in the lightbox come from the title tag that’s added to the link (the a tag). WordPress does not add those in galleries. You can add a filter to change that if you want to.
To do that, add this to the bottom of the functions.php file:
Be sure to copy that code directly from the support site and not the notification email.
That will set the title of the image to be the caption. Just make sure to enter a title for your images so you don’t end up with a file name there.
Bill