Per-format composition
Each aspect ratio receives its own crop. Smart focus, a chosen focal point or strict centering stays under your control.
Tap the source preview where attention should stay.
Before you start
A social image is made for a crop you do not control. The same file is shown as a wide card in one place, a square in another and a circle-masked thumbnail in a third, and each platform revises those rules without telling anyone. Designing for the specific pixel sizes of one platform is how an image ends up with its subject cut in half somewhere else.
What catches people out
Keep everything that matters away from the edges
Assume the outer band of the image may be cropped on some surface. Text and faces belong in the middle. This single habit survives platform changes better than any table of current dimensions.
Small text is the first casualty
A card that looks fine at full size is often shown at a third of it in a feed, and then recompressed. Type that reads comfortably in the preview can be unreadable where it actually appears. Check it at the size it will be seen, not the size you are editing at.