That's not a sneaky feature; it was the primary selling point when Google launched the new Photos product in 2015.

All modern gallery apps have some rudimentary photo recognition, but I haven't found any but Google's that will allow you to search terms like "topless/nude" and find accurate results. I would never store photos like that with Google, but I've confirmed it works, and with how many promotions Google has run offering free photo storage with their latest phones there are undoubtedly thousands and thousands of unwitting users who have sensitive photos not just automatically backed up in some Google server, but categorized. Just imagine if these servers were to be hacked and that information was conveniently pre-arranged for extortion.

I understand image recognition searching for generic terms like "cars", but my point is this can even recognise brands. And it only returns photos matching that brand, so it isn't replacing "Rolls Royce" with "cars" to do the search.

I guess it makes sense to do this, given that most things they do is based selling ads, I'm just surprised it is this accurate.

iOS photos app does this as well.

It does generic terms like "cars", but it doesn't work for specific brands (at least on my 5S).

Samsung gallery app does this as well. You can even search for stuff like "selfie".

Maybe every photo using the front camera is a selfie?

Didn't think of that obvious solution!