[outworlder]

"Select all pictures with a bow"

Then you have an actual bow. Like in archery. Next to a bowtie. Ok fine.

"Select all pictures of glasses"

Now you have a glass window. And glasses, as in spectacles.

Holy crap, that triggers me.

[makomk]

Don't forget all the people who are, you know, bowing. Seriously, I'm pretty sure it rejects your captcha if you do. Sheer evil genius all the way through.

[kalleboo]

I liked the "checks" where there were chess moves.

[TheRealSteel]

Clever. I would have gone with 'Select all images related to set'. If I recall correctly, 'set' has the most definitions of any English word, plus it could lead to some interesting contradictions, paradoxes, and confusion - any answer could be right!

https://en.wikipedia.org/wiki/Russell%27s_paradox

[mistro]

I'm pretty sure it changed relatively recently and is now "put", which has over 200 definitions (many of which overlap with "set")!