I also assumed those were going to be links, but after a second of confusion I really liked the side pane with animations. It adds a lot to the article and it's more pleasant than the usual alternatives (lightbox on top of the text, or opening a bunch of tabs).
Off the top of my head, I'm not sure how else you'd visually communicate "this bit is interactive on click/hover but isn't a link." Maybe a different text color (without underline), background color, outline (replaced by the colored highlight bar on hover), or a slightly larger and more distinct icon to replace the generic 'image' icon?
Off the top of my head, I'm not sure how else you'd visually communicate "this bit is interactive on click/hover but isn't a link." Maybe a different text color (without underline), background color, outline (replaced by the colored highlight bar on hover), or a slightly larger and more distinct icon to replace the generic 'image' icon?