Shifting Image with MATLAB Code [closed]

img = rgb2gray(imread('lena.bmp'));

imgFirstHalf = img(:,1:2:end);

imgSecondHalf= img(:,2:2:end);

implay(cat(3,imgFirstHalf,imgSecondHalf))


Now the question I have is, relative to the first frame, how should the second frame look like as in moving left or to its right?

I think the second frame should move to the right because the pixels in the second image are actually to the right relative to the first image(it can be seen from the way the images are created), but I am visually experiencing it the other way. Can somebody explain me what is going wrong with my thought process?