Ways of making sections of or elements in a picture clickable or hover-overable for more info, eg thinglink

For years I've wanted to be able to do this but had no idea how and then this year I've seen two examples that have intrigued me. The way I understand these services is as a cross between a Pinterest board and Google maps where a circle is 'dropped' onto an area of a picture and you can overlay information. When the person looking at the photo hovers over that circle they'll get the information, and with 'thinglink' they can actually click through to a linked website.

I think this is terribly clever and am keen to try it out myself.

The first example I ever heard of was from @Documentally who used thinglink to show "What's in my kitbag (Early 2015)?". I can't think of a more perfect use of the app / technology for that sort of thing, here's a before hovering and after hovering screenshot. On Documentally's post you can click on the blue circle to visit the Tom Bihn website.

The other example I've seen relates to this problem that politicians have with their posh kitchens. Here, The Telegraph has gone through items in a photograph of David Cameron fetching something from his fridge and labelled them with further info. As far as I can tell each bit of information isn't clickable though.

As far as I can tell the graphic, made by Mark Oliver, hasn't come from something I can play around with on the web - I didn't find anything obvious in the source code at least (tho not that certain what I'm looking for).

What other examples are there of this sort of thing? Free? Paid-for?