What site was that? Even if it doesn't exist anymore I might be able to find something based on the old URL in the Wayback Machine.
I haven't played with the picture grid captchas with a screen reader, but if they used useful alt text that allowed you to choose based on the question asked that would be very useful.
Brian - Windows 10 Home, 64-Bit, Version 1803, Build 17134
The psychology of adultery has been falsified by conventional morals, which assume, in monogamous countries, that attraction to one person cannot co-exist with a serious affection for another. Everybody knows that this is untrue. . .
~ Bertrand Russell