While the actual link change isn't that hard. Couple of lines each to add the link to Link, the processing of the parameters, displaying a fullsize image and displaying a slideshow, plus a new module to do the heavy lifting.
But I've only invested effort using with my enhanced reDesign3, called rD3Plus, and with the lightbox-like display (it's not lightbox, just a Dynamic Drive js/css script). So don't know how well it'd run on, say, default or dragonfly theme.
But anyway, I've got a problem to solve if the remote image gets deleted. Nothing fails, but it leaves the user with the grey overlay displayed!