There's a sort of... Sheen, to a lot AI images. Obviously you can prompt this away if you know what you're doing, but its developing a bit of a look to my eye when people don't do that.
It could, but the double spiral in the shell indicates AI to me. Snail shells don't grow like that. If it was a manual job, they would have used a picture of a real shell.
Edit: plus the cat head looks weird where it connects to the head, and the markings don't look right to me.
Also the fact that the grain on the side of the shell is perpendicular to the grain on the top, and it changes where the cat ear comes up in front of it.
Very telltale sign of AI is a change of pattern in something when a foreground object splits it.
Not saying it's always a guarantee, but it's a common quirk and it's pretty easy to identify.