Not hard.
Your suggestions requires the exercise of the observer to use imagination and perception
to determine a perceived difference.
I ain't buying it!!!!
I found it pretty quick too - It wasn't hard, but I don't see a second one.
Nikos (06-21-2020)
OK, I saved the picture and enlarged it as much as I could with Paint. As you can see, at the pixel level there are slight differences around in the eye and the mouth.
If that is what you meant fuego, well spotted.
fuego (06-21-2020)
Romans828 (06-23-2020)