I've got some slideshow gizmos to try out, but that will come later. Got to get the HTML/CSS in order first.

Prism, from what little I could grasp... it seems one way to deal with images in responsive sites is to set up an array or database that includes all the sized versions of each image, then there's some sort of PHP script to pull in whichever image is needed.
https://www.callendales.com