Speaking as an amateur Photoshop wizard, it's obvious that those photos don't represent a real airbrushed skirt but (as they point out) some kind of digital editing. All of them appear to present a precise and correct image to the camera, despite the various angles at which the women are standing. True "trompe l'oeil" illustrations usually only work from a single angle. Such a skirt might work if you were looking at it straight from the back.

Remember that pivotal scene from "Indiana Jones and the Last Crusade?" He has to step out over what appears to be a sheer cliff, only to step onto a cleverly painted bridge that perfectly matches the background and appears "invisible." Unfortunately, it perfectly matches the background from the camera's angle, not Jones' viewpoint. The many camera angles on this scene in which the bridge is still "invisible" makes even that idea ludicrous. The idiot even throws sand on it as though the camouflage worked from the other side!

Anyway, in real life, with human 3D vision, such a gimmick wouldn't work very well even if the angles were right.

If it had been me, I would have tapped the air off the edge with my foot before walking out.