OK... Bootstrap Update.
Have tested Bootstrap carousel for post attachments and Bootstrap does not work as good as our current attachment code using Swiper
Swiper - Most Modern Mobile Touch Slider
So, will
not transition our attachment code in posts to Bootstrap from Swiper.
Bootstrap Carousel seems great if we had some big banner of slides at the top of a page with a bunch of images in carousel, which we don't have or need.
However, I may consider Bootstrap Carousel for the albums, but at this times, seems not necessary.