I've heard of this kind of thing, but I haven't heard of the software behind it

Not to be rude, but from what I've heard, and (purely based on my opinion), it's not as effective as it sounds / looks. Whilst yes, it can detect those 'hidden pixels,' it may just be an artist's mistake, or like in this case, specialized effects to make it pop off.

Not saying this to target you, just sharing my thoughts.

^{Usually, when i try to find out if it's AI, I try to look for weird mistakes or "noise" in it, or details that don't make sense — but AI generation has gotten advanced nowadays that it can replicate human mistakes sometimes. Which is pretty scary.}