Why a shape has to be right at generation
Resolution can be revisited after a render and shape cannot. A crop keeps a rectangle from inside the frame, so everything outside that rectangle is gone, including whatever the composition was built around. As of 2026-09-12.
| Change | Recoverable from a master | What it costs |
|---|---|---|
| A tighter version of the same shape | Yes | Resolution, which is usually spare |
| A different shape, subject centred | Sometimes | The edges of the composition |
| A different shape, subject off centre | No | The subject leaves the frame |
| A longer version | No | Nothing exists outside the master |
Inclusion rule. Changes a delivery team is commonly asked to make from a finished master. Regeneration is treated as a new piece rather than a change. Order. Cheapest change first.
1A crop is a choice about what to lose
Going from widescreen to vertical keeps roughly a third of the width. Going to square keeps rather more. In both cases the decision is which third of the picture matters, and it was made when the shot was staged rather than when the crop was applied.
A subject placed centrally survives most crops. A subject placed by the rule of thirds, which is the ordinary instinct and often what a generator produces, does not.
2Composing for the tightest crop is the usual compromise
Where one master has to serve several surfaces, the workable approach is to stage for the tightest shape and accept dead space in the others. That costs a little in the widest placement and avoids regenerating the piece.
It has to be decided before generation, in the prompt or the shot list. Asking for a centred subject with clear space at the edges costs nothing at that stage and cannot be added afterwards.
3Generating per shape is better where the page allows it
Where a page publishes several shapes as a parameter, each surface can have its own staging and no crop is needed. That is the argument for a long shape list, and it is a separate question from picture quality.
Where the page publishes one shape, or none, the crop is the only route and the composition has to be built for it from the first attempt. Discovering that at the edit is the most expensive way to learn it.
A craft note, not a spec. Nothing here is taken from a platform or a vendor, and nothing here should be quoted as a requirement. The sourced material is on published limits. Related: Tier names, Sound with the picture.
4A generator's ad pipeline
For ad work around “The crop that costs”, SceneMixer's pages explain how its ad projects are produced:
On a segment’s card, Insert adds a blank segment right after it: write its header and shots.
SceneMixer, Inserting and Deleting Segments (read 2026-10-13)
For places, every photo you add becomes a set the shots can move through, up to four.
SceneMixer, An AI Ad for a Store or a Property — “Can I add several rooms?” (read 2026-10-13)