Aspect ratio — the relationship between an image's width and height — quietly controls how your pictures look in feeds, headers and galleries. Get it right and images fit cleanly; get it wrong and they stretch, crop awkwardly or letterbox.
What aspect ratio means
An aspect ratio like 16:9 means 16 units wide for every 9 tall. It is independent of resolution: 1280×720 and 1920×1080 are both 16:9. What matters for layout is the shape, not the pixel count.
Ratios worth knowing
- 1:1 — square; profile pictures, many social posts.
- 4:5 — portrait; the tallest that fits well in most social feeds.
- 16:9 — widescreen; video thumbnails, headers, hero banners.
- 9:16 — vertical; stories and short-form video.
- 3:2 / 4:3 — classic photography ratios.
Crop, don't stretch
To change an image's ratio, crop it — remove pixels from the edges. Never stretch to fit, which distorts faces and shapes. Most tools let you lock a target ratio and slide the crop box to choose what to keep.
Keep the subject balanced
When cropping, leave a little breathing room around the subject and mind the horizon. The rule of thirds — placing key elements a third of the way in — usually produces a more natural composition than dead-centre.
Plan for multiple ratios
If an image will appear as a square thumbnail and a wide banner, shoot or choose it with room to crop both ways. Composing a little loose gives you the flexibility to reframe for each placement without losing the subject.