Adobe Photoshop – when used right – can be an extremely powerful photo-editing tool. It’s the only photo manipulation app, after all, that I can use to superimpose myself on top of mythical creatures, or to pretend that I’ve met various celebrities all far cooler than myself. But when placed in the hands of an inexperienced user, horrible things can happen. Hands disappear, lighting turns harsh, and levels go awry. People can die.

But in all seriousness, the fact that Photoshop has become so prevalent means that almost anyone can produce a photoshop – and more often than not, with less than pleasing results.

Case in point: The front cover of this year’s City of Toronto’s FUN Guide! As the National Post aptly pointed out, the cover of this year’s parks and recreation guide is not what it seems. Apparently city employees felt it necessary to do a little photo manipulating of their own, replacing the perfectly acceptable stock photo Latino patriarch with an African-Canadian male.

Say what?

While there’s already quite a bit of discussion going on in the National Post’s comments section, what I find most interesting is how exactly Post’s graphic designer was able to uncover this in the first place. I mean, from looking at the image, it’s clear that the cover is an incredibly blatant shop – the man’s expression is far too creepy for the rest of the family’s joy, his forehead is very poorly lit, and those fingers floating beside his neck? Clearly dismembered.

But recognizing that something is a Photoshop doesn’t magically grant one the ability to see through layers of manipulation. No, for that the Post consulted the omniscient knowledge of online search engine TinEye, an advanced image recognition tool that “detects visual enhancements to standard art.”

So where exactly does all of TinEye’s magic smoke come from? According to the search engine’s website, every image has something amounting to a fingerprint – a unique identifier different from other images.

Well, almost unique, anyhow. Apparently, modifying an image in certain ways – a la the City of Toronto – still retains much of the image’s original fingerprint, if not all of it. TinEye will scan a user-submitted photo, and compare its fingerprint against others in the database. In this case, the image matched.

So what exactly is this piece of software good for? If you count the defeat of photoshop-claiming trolls across the internet as a use, then you’ve already got one. But for news organizations and journalists like those at the Post, this sort of software could be invaluable. Imagine being able to quickly and easily confirm a manipulation like this without a doubt – making fakes much less of a reality.

Of course, the only caveat is that the original photo has to have been used already on the internet is some capacity, as was the case with Toronto’s FUN Guide. But as long as the image exists in some form – even cropped, or with adjusted levels – then you can bet it has an online history just waiting to be uncovered.