Hi Barry, Welcome to the Forums.
Thanks for posting the thumbnail.
The first rule that came to my mind was “No guns pointed at viewer” - But this is the opposite of that! I wonder if the moderator got that rule mixed up…
There’s also a part in the ESRB link that mentions “crosshairs placed over heads/faces” - But this is clearly a sniper aiming at the center of a humanoid fish, preparing to end its life in the cleanest and most humane way 
Another line from the rules is that “All images should “be engaging”” - Which is super subjective, but I wonder if adding the title of your experience to the thumbnail would make any difference.