The images itself were all pixels are comparedwith each other.
pixel 1 of image 1 = pixel 1 of image 2(or x)?
pixel 2 of image 1 = pixel 2 of image 2(or x)?
:
pixel 1 of image 1 = pixel 1 of image 2(or x)?
pixel 2 of image 1 = pixel 2 of image 2(or x)?
: