Lock the ratio so faces do not stretch
With the ratio locked, changing one side moves the other and the photo keeps its shape. Unlock it to force a photo into a fixed frame — but if that frame has a different ratio from the original, faces come out long or wide.
To fit a frame without distortion, crop to the right ratio first and resize afterwards.
The sizes worth knowing
- Square, 1080 × 1080 — the ordinary feed post.
- Portrait, 1080 × 1350 — takes more of the screen than a square, and suits full-length wedding photos.
- Story, 1080 × 1920 — fills a phone screen.
- Cover photo, 1640 × 856 — the banner on a profile.
Enlarging does not add sharpness
Turning a small photo into a large one invents no detail; the browser only stretches the pixels that were already there, and the result is soft. Always start from the largest original you have.