Aspect ratios for AI images: which frame to pick
1:1, 4:5, 3:4, 2:3, 16:9 or 9:16? What each frame is for, how it changes composition, and how to prompt for it.
The aspect ratio is the first compositional decision in any image, and with AI it matters even more: the model composes the scene to fill the frame you give it. Ask for a wide landscape in a tall frame and it will either crop the landscape or invent sky and foreground to fill the space.
The frames and what they are for
1:1 - square
Balanced and centred. Good for single objects, icons, album-style artwork and profile images. Square frames reward symmetry and a subject placed in the middle.
4:5 - tall portrait
The tallest frame most social feeds show without cropping, so it takes up the most screen space in a scroll. Strong for products, food, architecture details and anything with vertical lines.
3:4 and 2:3 - classic portrait
The proportions of print photography and posters. 2:3 is the shape of a 35mm frame turned upright; it suits editorial images and book or poster covers.
16:9 - widescreen
The shape of screens and video. Use it for landscapes, interiors, website headers, presentation slides and any still you might later animate into a clip for a horizontal video.
9:16 - vertical full screen
Phone wallpapers, stories and vertical video. It fills a phone screen edge to edge, but the frame is narrow: keep the subject simple and stacked vertically.
Prompting for the frame
Write a scene that belongs in the shape you picked. For wide frames, describe things side by side: "a row of fishing boats along the harbour". For tall frames, describe depth or height: "a spiral staircase seen from below", "a tall glass of iced coffee with layers".
A narrow alley in an old harbour town at blue hour, lanterns receding into the distance, wet cobblestones, looking straight down the alleyA long wooden pier stretching across a calm lake at sunrise, low mist, mountains on the horizon, wide shotWhen you are not sure
Render in the largest frame you might need and crop later, rather than the other way round. A 16:9 image can be cropped to a square; a square cannot become a wide banner without inventing the missing sides.
