Which aspect ratio should I use, and how does it change the image?

Aspect ratio determines what the model composes, not how it's cropped afterwards. Portrait frames push subject-dominant compositions, wide frames push environmental ones, square sits between. Choose it before you write the prompt, and match your camera language to it.

The single most common misunderstanding about aspect ratio: people treat it as a delivery format decided at the end. It isn't. The model composes for the frame it's given, so ratio is one of the first decisions, and it silently rewrites everything downstream — subject scale, how much environment exists, where the eye lands.

What each frame tends to produce

FrameWhat the model tends to doGood for
Portrait (2:3, 3:4, 9:16)Fills the height with the subject; minimal environment; tight headroom; strong central verticalPeople, single objects, product shots, anything for phones or Pinterest
Square (1:1)Centred, balanced, subject at medium scale with a readable but secondary backgroundFeed images, thumbnails, icons, catalogue grids
Landscape (3:2, 16:9)Subject placed within a setting; genuine negative space; horizon-driven compositionScenes, environments, banners, anything where context is the point

Try the same subject in two frames and the difference is not subtle. 'A lone figure on a salt flat' in portrait gives you a person, with a bit of salt flat behind them. The same words in 16:9 gives you a salt flat, with a small person in it, and the emptiness becomes the subject. Neither is more correct — but if you wanted the second and asked in portrait, no amount of prompt rewriting will fully recover it.

Match your camera language to the frame

Frame and lens language reinforce each other, and they can also fight. Asking for a 'wide establishing shot' in a 9:16 frame gives the model contradictory instructions: the words want breadth, the canvas wants height. You typically get a compromise that reads as neither — a cramped landscape, or a vertical image with a strangely squeezed horizon.

  • Portrait pairs with: close-up, medium shot, 85mm, shallow depth of field, low angle, subject fills the frame.
  • Landscape pairs with: establishing shot, wide angle, 24mm, deep focus, rule-of-thirds placement, layered foreground and background.
  • Square pairs with: centred composition, flat lay, symmetrical framing, top-down.

Don't fix framing with a crop

Generating wide and cropping to portrait afterwards costs you resolution in the dimension you kept, and leaves a composition designed for a frame you're no longer using — the subject sits where it made sense in the wide version, which usually means dead-centre and too small. Regenerate in the target frame instead. It's cheaper than it sounds and the result is composed rather than salvaged.

How this shows up on the site

Every prompt page here records the orientation its image was generated at, right in the parameter table, and the composition of the resulting image is classified separately — centred, rule of thirds, symmetrical, and so on. Those are two different things and it's worth seeing them apart: the same portrait frame can hold a tightly centred subject or an off-centre one, and the composition pages let you browse by the result rather than the container.

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