I think how open ended it is matters, as well as how quickly you can look at an image vs read a submission. Even on r/writingprompts, I always read a few and then moved on, while I could keep going on and on on PSBattles, because each image was just a glimpse and what they did with it was so different (at least it felt like compared to how writing prompts usually went). And personally, I agree about pivoting to a generic name.
Heil five!