How does Max Pooling (of size 2x2) change the size of receptive field in CNN?
Before anything, let's try to understand what Max-pooling actually does. Intuitively, Max-Pooling takes the maximum of the value inside the kernel as the maximum value is something that causes a larger impact from the picture. When the size of the kernel is 2x2, half of the values denote the actual value so the receptive field increases. A visualization could be found in this video. Also you can look at this video too