Hi John, what is happening is that for the dog image, there are 618 rows, and to fulfill the  new size of 11002 columns, the rows are alternatively placed in the same row. .For example, 1st row remains in the same place, the 2nd row is picked and placed adjacent to this 1st row. The rows of the dog image are placed alternatively in adjacent manner due to which there are 618/2 rows in the first dog image and the remaining 618/2 rows are in the 2nd dog image. so it is basically rescaled to 3142200. The same explanation goes for the cat image. Hence, the images are not cut in half horizontally but rescaled.