Why the box matters before the pixels
A square is not a style choice so much as a contract with the surface that will display the file. Chat avatars, many app icons, and a lot of marketplace thumbs are 1:1. If you upload a wide landscape, the host will zoom until the short side fills the hole — usually cutting ears, type, or product edges. This page is for that contract: lock 1:1, or switch to another named ratio when the destination is not square. Classic print habits still show up on the web: 3:2 from many still cameras, 4:3 from older compact sensors and slides, 5:4 from some portrait print houses. Widescreen heroes and YouTube-like players want 16:9. Stories, Reels, and phone-first ads want 9:16. None of those should be faked by stretching. Stretching distorts faces and logos; trimming keeps geometry honest. Composition inside the locked box still matters. Rule of thirds puts eyes or a product’s visual weight on intersections instead of dead center. A golden-ratio spiral is a softer cousin of the same idea — useful when a portrait feels cramped once the sides are gone. Leave a little breathing room: circular avatar masks will eat corners that looked fine in a square preview. If you need exact pixel counts after the ratio is right (1080×1080, not merely 1:1), continue on the pixels spoke or Image Resizer. iPhone HEIC should become PNG or JPG before Canvas can lock the aspect. Eligible jobs stay free in this tab.