This page is an entry in the Key.

stretching a photograph
vertically or horizontally

Unless the photograph was taken with an anamorphic lens, visually stretching a photograph either horizontally or vertically — even by a tiny bit — always disqualifies a photograph from Q2.

That is because everything in the photograph is reshaped by such actions.

The only reason that anything in TCQ photographs can ever be reshaped is to correct for camera/lens/shutter anomalies, including use of anamorphic lenses.

Note that cropping and overall resizing do not disqualify photographs from TCQ.