Correct sizing is a production requirement
A square image stretched into a carousel or a headline placed inside a crop zone is not a cosmetic mistake; it makes the asset unusable. Format is chosen before rendering, with stable dimensions and text hierarchy tied to that surface.
The current defaults are 4:5 for carousel slides and 1:1 for standalone image posts. Those defaults can be changed per channel strategy, but every output is explicit about its aspect ratio and content type.
