Comment by throwaway314155

It wasn't because it was "out of distribution" (although that's a reasonable assumption and it is at least _somewhat_ out of distribution, given the scarcity of your examples).

Like the avocado armchair before it, the real reason was simply that it "looked cool". It scratched some particular itch for people.

For me, indeed it's correlated with "imagination". An avocado armchair output had a particular blending of concepts that matched (in my mind) the way humans blend concepts. With the "astronaut riding a horse on the moon", you are hitting a little of that; but also you're effectively addressing criticism about text-to-image models with a prompt that serves as an evaluation for a couple of things:

1.) t2i is bad at people (astronaut)

2.) t2i struggles with animal legs (horse)

3.) t2i struggles with costumes, commonly putting the spacesuit on both the astronaut _and_ the horse - and mangling that in the process (and usually ruining any sense of good artistic aesthetics).

4.) t2i commonly gets confused with the moon specifically, frequently creating a moon _landscape_ but also doing something silly like putting "another" moon in the "night sky" as well.

There are probably other things. And of course this is subjective. But as someone who followed these things as they happened, which was I believe the release of DALL-E 2 and the first Stable Diffusion models, this is why I thought it was a good evaluation (at the time).

edit: I truly despise HN comment's formatting rules.