There are some puzzles on this site that involve images and recognizing what is on the image is a significant part of the puzzle, for example here. One can start solving puzzles like this in two ways. One can either look at the pictures and try to recognize what or who is on the pictures, possibly googling guesses to confirm/ reject them. Or alternatively one can reverse image search. There is some technical skill involved but it has nothing to do with the content of the picture. If the image is found, one immediately knows what or who is on the picture.

In the example I linked, I would say directly identifying the 4 people is much harder than solving the rest of the puzzle once you know who they are. The same puzzle with the names of these people instead of their pictures would be almost trivial.

So what is the general etiquette on using reverse image search on puzzles? Can the asker encourage/ discourage using this technique? Should answers include whether they used this to arrive at their answer?

I don't have any good answers to my questions but I feel the answers strongly impact how these kind of puzzles work.


1 Answer 1


I answered the puzzle you linked and of course I used reverse image search to identify the persons. This post has gotten rather long and blathery, so here's the synopsis up front:

Solvers may use reverse image search, but it's not a very interesting puzzle mechanic. If a designer wants to prevent reverse image search, the puzzle must make sure that an image search does not provide the answer.

Your question has two angles. First, from a solver's perspective: In my opinion, this puzzle screams "use reverse image search to identify the persons". The portraits are the only information we have and the depicted people are not really well known. I mean, I know that Rossini was an Italian composer of operas, but I don't know what he looked like. I had no chance of identifying the other three.

Reverse image search exists and it is the ideal tool to identify people from digital portraits. Cropping and uploading the images is tedious legwork. If you don't enjoy that, skip the puzzle.

Many puzzles have a knowledge element that requires some research. Some of them, such as country codes, capitals or chemical symbols, are puzzle staples, but still may require you to look up some data on Wikipedia. Others delve into obscure regions of knowledge and are research fests.

Research can be fun, but I don't enjoy the routine of doing reverse image search. In the case of the linked puzzle, there were only four images to identify, but if there are many images to identify, I'm usually put off the puzzle. (Occasionally, like in this here puzzle, I can take advantage of other people's reserach work posted in partial aswers. I'd never have gone through the trouble of identifying all these people, and I could't identify any of them from their photos. I couldn't identify some by their names, even.)

Second, from a designer's perspective: I don't think you can avoid that solvers use image search. Putting a moral ban on image search – "Please do not use image search" – will only draw the solvers' attention to it.

(Other types of puzzles, notably those tagged and , make it obligatory to write a detailed description of how the solution was arrived at. Well, I'm not particularly good at grid deduction puzzles, but having to write a scientific paper with many images puts me off answering these instantly. That doesn't mean that I don't try to solve the puzzle, but I sure would loathe to document my solving.)

Anyway, if you want to prevent solvers from using reverse image search, make the puzzle inaccessable to search. Your question mentions giving the names of the people outright, but there are other means:

  • Use images, but modify them, so that they are recognizable, but look completely diferent to a search engine. Just blurring may not do the job, but I can imagine that a different colour palette as in Andy Warhol's work or in Obama's Hope poster will work. There may even be online image filters for that.

  • Provide the information by other means, for example as text. "Composer of the 'Barber of Seville'" may be too obvious – if you don't know the answer already, it's also just a simple web search –, but perhaps you can find some aspect that makes the research more interesting. It may be necessary to provide some means of confirmation, for example the letter count (9, 7) for Gioachino Rossini. (But that will make people use that letter count in reverse word solvers like Qat or One look, of course.)

Another strategy, especially if you have many related things, is to make some of these things easy to find or even obvious, so that you can find the rest via a common link. That's not possible in the puzzle you linked, though.

  • $\begingroup$ Thanks for the detailed answer. I thought that the linked puzzle could be solvable by identifying one or maybe even two people from the pictures and then forward searching these people might give you an idea of the common theme and thus find the other ones. That would be much harder than reverse image searching though (I couldn't identify any of them either). $\endgroup$
    – quarague
    Sep 20, 2022 at 12:37
  • $\begingroup$ Relevant question on Graphic Design SE: Preventing reverse search engines from finding the origin of your image? $\endgroup$
    – HTM
    Sep 20, 2022 at 18:08
  • 2
    $\begingroup$ I'd also like to add that if the main goal of your puzzle is merely to identify the people/places/objects/etc. in a set of images, then it's likely not going to be a very interesting or engaging puzzle, even if you take precautions to prevent solvers from using reverse image search. Try mixing image identification with some other puzzle-y mechanism: both the questions that OP linked and the one in this answer are good examples of doing just that $\endgroup$
    – HTM
    Sep 20, 2022 at 18:17

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