Like a lot of people shipping iOS apps this year, I tried generating App Store screenshots with image models. GPT Image, nano banana — the results looked genuinely great. Then App Store Connect rejected them: wrong canvas sizes, subtly warped text, device frames that don't match any real device.
After the third rejection I realized the problem wasn't prompt engineering. Frames and canvases are geometry, and geometry is arithmetic — something a coding agent expresses perfectly in CSS, and something an image model can only approximate statistically. Asking a diffusion model to hit 1290×2796 exactly, with a pixel-true bezel and crisp 17px mono type, is asking statistics to do arithmetic.
So I split the work, and open-sourced the result as a skill for Claude Code and Codex: HyperShots.
The split: deterministic where Apple has rules, generative where it sells
Deterministic half (no AI involved at all):
