memes

Yes in the third picture which we all think she looks the best, there's more space between her arms and her body than there are in the other two pictures. They definitely shaved down something so she's thinner in the third picture.

When they said the same pose, they just mean they are front facing, arms to the side, as opposed to different positions for each dress. It's pretty darn close. She had to change dresses between shots, so the poses aren't going to be perfectly identical, but they are close enough to make the point that a person looks different depending on the stripes.

Do you really think that extra half inch of daylight between her arm and body somehow faked the result?

Also the i think the different collars matters. Low No collar, high black collar, high no collar.

I should really start eating my fries vertically

Yup.

So let's take the body/pose on the right, copy it to all three positions mask the dress only, and overlay only the dress pattern in the same mask to actually show the differences between the patterns only.

I agree with you, but if you measure the width of the dress at the tip of her fingers, the left and right are about 99-100 pixels, while the middle one is 105 pixels wide. Her face in all three images is about 38-39 pixels wide (measured at the earlobe), so that rules out they stretched the entire image slightly. But 5 pixels is significant enough to kind of muddy the validity of the OP's message since it no longer rules out all but the appearance of the dress. It sadly happens that sometimes effects are exaggerated, even when there is a real effect at play.

Bingo

Look at the amount of visible background inside the elbows. They are each increasing in conforming the body as you move to the right.

Loading it into an editor she has about an inch less per hip in the diagonal picture. Its pretty significant.

Ah I see it now. You can also tell by looking at the gap differences between her waist and arms.