Glossary
Aspect Ratio
Short answer
The ratio of an image's width to its height; it directly determines the composition.
Aspect ratio is not just a measurement but a composition decision. The model builds the scene around the ratio you give; 16:9 reads a landscape as wide, 9:16 reads the same landscape as a vertical slice.
So setting the ratio at generation time always beats cropping afterwards. Cropping breaks a composition; specifying the ratio builds one.
Common ratios: 1:1 (profile, square Instagram), 4:5 (vertical Instagram post), 9:16 (stories, Reels), 16:9 (YouTube thumbnails, slides), 2:3 (posters, Pinterest).
Example
Use `--ar 16:9` in Midjourney and the ratio selector in Leonardo and Ideogram. Bing Image Creator produces squares only.
See also
You will meet this in
- Midjourney — The Aesthetic Quality LeaderThe subscription generator that delivers the most consistent artistic and aesthetic results.
- Leonardo AI — Generation on Free Credits That Renew DailyFree credits that renew daily, a large model library and dedicated tooling for game assets.
- Ideogram — The Best Tool for Text Inside ImagesFor logos, posters and typographic design: the one tool that gets the lettering right.