AI or real? The quiz

B is AI-generated (ChatGPT). Everything is sharp at once, from the pigeon’s feathers to Big Ben across the river, where a camera this close to a bird would blur the background. It is also a postcard: Big Ben, Parliament and two red buses, all perfectly placed.

A is a real photo taken by Westminster Bridge. The background is soft, one pigeon half-hides the other, and the ledge is stained.

A is AI-generated (Grok). Check the bottom-right corner: a faint “Grok” mark, which xAI’s generator stamps on its images. The “writing” on the grey sweatshirt in the middle is scribble, not letters.

B is a real photo from Tulane University’s library: ordinary clutter, a bag on the floor, a laptop, a student half out of frame and uneven daylight.

B is AI-generated (Google Gemini). The box she is reaching into says “QUINO” above a picture of cookies, and the small print on it is letter-shaped noise. The pantry is spotless and lit like a film set.

A is a real photo: the lens blurs the background into soft points of light, and the biscuit has a real, uneven bite taken out of it.

A is AI-generated (Google Imagen). The light is golden from every direction at once, the cabin, fence and path sit exactly where a painter would put them, and the rocks along the river are evenly scattered.

B is a real photo of Yosemite Valley and the Merced River: harsh midday light, a washed-out sky and branches in the way, the untidy details nobody arranges.

B is AI-generated (Stable Diffusion XL). The signs look like Chinese from a distance, but the characters are not real ones: they are shapes that imitate lettering. The number plate on the yellow car is gibberish too, and the street glows in every colour at once.

A is a real photo in Hong Kong: every sign reads as real words, one of them “Koon Nam Wah Bridal”, and the street is full of people going about their evening.

A is AI-generated (FLUX, according to its uploader). It looks like a soft toy: fluffy white fur on the face and chest, glossy black bead eyes and neatly striped spines, posed on a log in front of a background melted into blur.

B is a real photo: a wild hedgehog in rough grass, with coarse brown spines, blades of grass across its body and no pose at all.

B is AI-generated (Midjourney). One of the hardest rounds. Look closely at the skin: the pale speckles are spread as evenly as a printed pattern, and the one highlight has a faint rainbow tint. The rest is simply too perfect, down to the evenly woven cloth.

A is a real photo taken in a studio: the cut half shows the core and seeds, and the reflection on the black glass underneath matches both pieces.

A is AI-generated (Adobe Firefly). The sun trails a long straight streak down the sky, and the snow lies in even parallel stripes down every slope, as if combed. The colours are turned up everywhere.

B is a real photo, and the one that looks less believable: sunrise from a ridge on Monte Rosa in the Alps. Look for the climbers on the rocks. Real skies can be this dramatic.

B is AI-generated (DALL·E 3 in Microsoft Copilot). Look past the cat. The jars and pots on the shelf never turn into anything you could name, and the light comes from everywhere: golden sun striping the wall, a glowing bulb above, and the cat lit perfectly from the front.

A is a real photo: a cat crouched on a ledge beside a pot of pansies, with a rusty bit of metal next to it and a slightly wary look.

A is AI-generated (Google Gemini). The cracks in the plaster look painted on, and the dry-stone walls are stacked a little too neatly, leading the eye straight to the door. The whole scene glows in one soft golden light, like a painting of a chapel.

B is a real photo: a small roadside chapel with a patterned tile roof, a gutter downpipe and a paved path, in ordinary grey weather.

B is AI-generated (ChatGPT). Its Commons page says it was generated from the real photo, A. The stone bell tower of the harbour chapel seems to grow out of the boat’s deck, where the real photo shows it on the shore behind. The colours are pushed, and every patch of rust is crisp at once.

A is a real photo: the wrecks at Camaret-sur-Mer in Brittany on a grey day, soft, untidy and half-collapsed.